Unit 7bc Book

1. Introduction

Unit 7bc follows from Unit 7a, which means it expands the topic of security further. You will learn how to describe an incident, i.e. how to talk about simultaneous and consequent past events. In addition, you will find out how some of the security devices work. This means that you will learn how to explain technical principles using the Present Simple tense. In such situations, the Present Simple tense is necessary because a principle is something that does not change over time, but stays the same. Finally, you will have a chance to express your opinion on some security devices and pick the one that you think is the most useful and suitable for a particular purpose.

Contents:

Describing a technical principle using the Present Simple tense; using the Past Continuous tense to talk about simultaneous actions:

• Each pulse generates a magnetic field in the coil.
• While a passenger is walking through the walk-through metal detector, the alarm sounds if he has some metal objects.
• While the passenger is walking through the walk-through detector, the official is studying a screen on a display unit.  

Talking about simultaneous past events using the Past Progressive/Continuous tense:

• While a passenger was walking through the walk-through metal detector, the alarm sounded.
• While the passenger was walking through the walk-through detector, the official was studying a screen on a display unit.

2. Warm-up: Listening

In Unit 7a, you read about a security incident at the airport. Basically, there were three parts who played a key role in it: the inspector disguised as a passenger, the security official and the walk-through metal detector. Surprisingly, it was the official, not the airport metal detector, that caused the incident. Very often, some incidents and even accidents do not happen due to a technology failure, but due to a human error. This time, the walk-through metal detector (WTMD) was fault-free. By reading a technical text, you have even had a chance to find out how it works, so now it should not be so difficult for you to watch the video at… and complete this listening comprehension task.

3. Grammar: Describing a Principle vs. Talking about Parallel Actions Happening in the Past

To describe a principle of a machine, the Present Simple tense is usually used because it describes something which is either repeated or which is always true:

Coils create a magnetic field. They are embedded in the WTMD frame.

This tense was covered in the AEL3 course, but if you feel you need to revise it, look at this grammar overview.

However, in some specific situations, the Present Continuous/Progressive tense can be used. For example, you can use it to distinguish between aspects:

When/After a passenger walks through the metal detector, a magnetic pulse is sent into the opening.

You can also see that this sentence means that the action expressed in the subordinate clause after “when/after” is finished first – before the action expressed in the main clause starts:

Když člověk projde detektorem, do prostoru je vyslán magnetický puls. (přítomný prostý čas pro vyjádření dokonavého vidu, tj. děj vedlejší věty po “when/after” je napřed dokončen, než nastane děj věty hlavní).

vs.

When/While/As a passenger is walking through the metal detector, a magnetic pulse is sent into the opening.

Když člověk prochází detektorem, do prostoru je vyslán magnetický puls. (přítomný průběhový čas pro vyjádření nedokonavého vidu)

You can see that the Present Continuous/Progressive tense is used to talk about a situation in progress (is walking) which is interrupted by a short action (... is sent... – the Present Simple tense). In other words, in one short moment, the two actions happened parallelly. This means that you can also use the Present Continuous/Progressive tense to talk about parallel actions that are in progress at the same time:

When/While/As a passenger is walking through the detector, his/her bag is going through the X-ray machine.

Here, the two parallel actions take some time. This is a rather rare use of the Present Continuous/Progressive tense, as you can see if you compare it with its common uses in this grammar overview.

 However, where a continuous/progressive tense is used very often is when you want to talk about parallel actions happening at the same time in the past. In such a case, the Past Progressive/Continuous tense is used. Look at the sentence below and compare it with the sentence in the Present Progressive/Continuous tense to see the analogy:

 When/While/As a passenger was walking through the detector, his/her bag was going through the X-ray machine.

As you can see, the two actions were happening in parallel for some time. Similarly:

When/While a passenger was walking through the metal detector, a magnetic pulse was sent into the opening.

Here, however, the action in the main clause took just a fraction of a second; therefore, the Past Simple tense is used. These two types of sentence must be distinguished from the one below:

When/After a passenger walked through the metal detector, a magnetic pulse was sent into the opening.

Here, the actions are not parallel, but consequent with the action expressed by the subordinate clause after “when/after” happening first. Therefore, no continuous tense is used, but there is the Past Simple tense in both the clauses. Now, read about the use of the Past Progressive and Past Simple tenses in this grammar overview. After that, see if you understood the overview fully and complete a similar one here. Then practise this grammar point first in the context of airport incidents , then in the context of an electrical accident, and finally in the context of accidental technical discoveries.

4. Listening: Other Security Systems

Besides walk-through metal detectors, there are also other security systems. If companies want to make their headquarters more secure, they can choose from a range of options, for example, passwords and pin numbers or various biometric devices, such as signature verification systems, iris scanning, voice recognition, face recognition, vein scanning, hand scanning or fingerprint scanning. In recording 22 that comes with your coursebook, Bob is trying to find the best security system for the offices of his company. Which of the systems listed above do you think he will choose? Listen to the recording to find out. As you listen, complete this listening comprehension task. Alternatively, you can read the transcript of the recording on pp. 122-123 in your coursebook (Bonamy, D. (2011). Technical English Level 3 Coursebook. Pearson Longman).

5. Specialist Reading: How does Fingerprint Scanning Work

If you listened carefully to the recording in the listening task in the previous section, you know that Bob selected capacitive fingerprint scanning. But way? Well, he probably had two reasons. First, he found some interesting facts on fingerprints. If you scan the text on p. 116 and complete this task, you will have the same data. You must be pretty quick because there is a time limit of minutes set.  In addition, Bob has found some technical facts and explanations on the scanner. Before you read the same text as Bob, look at some useful electrical vocabulary. Just match words to the components in this vocabulary task. Then read a text about fingerprint scanning and do this quiz. To complete this task, you will need to look at diagrams on p. 56 in your coursebook (Bonamy, D. (2011). Technical English Level 3 Coursebook. Pearson Longman).

6. Forum: Security Systems

Based on what you heard in the listening task in Section 4 and on what you read in Section 5, what do you think the best security system is out of these:

walk-through metal detectors, passwords, pin numbers, signature verification systems, iris scanning, voice recognition, face recognition, vein scanning, hand scanning, fingerprint scanning.

Why do you think so? What are the pros and cons of the individual systems? Discuss this topic in this forum. If you need more information on the systems before you discuss them, google some facts from reliable sources.

7. Writing: Security Systems

So far, you have listened to info on security systems and read about some of them. Now, you are asked to write about one of them. You can either summarize what you have learned about:

a) walk-through metal detectors

or

b) fingerprint scanning

or:

you can select one of the systems from this list: eye scanning, hand scanning, face recognition, voice recognition, an antivirus program (with each of the systems, you will be provided with some clues).

Write at least seven sentences. Submit the finished task as a Word document via this portlet in Moodle.

8. Word list

The key terms related to the topic of Unit 7bc can be found:

• in the Excel format here.
• in the interactive flash card format here. This format is particularly good for drilling the new vocabulary.
• in a zip file here. This file is downloadable, so that after unpacking it, you can drill the new vocabulary on your desktop, laptop or any other portable device where you have a browser installed. The recommended one is Mozilla Firefox. Important: after unzipping the zip file, make sure to keep all the related files in the same directory at all times. Do not change any file names and do not transfer or delete anything.

Recommendation: Remember that the best way to learn new vocabulary is to see each new word in a context; that is, seeing it in the contexts provided in the tasks you complete in the unit.

9. A printer-friendly version of Unit 7bc

A printer-friendly version of Unit 7bc exercises and the keys to these exercises can be found here.