CAN – be able to do smth. / be capable of doing smth

Notes:

1. Can has only two tense forms: can (present) and could (past), so for other tenses to be able to do smth. or to be capable of doing smth. are used. But if you mean that someone managed to do something in one particular situation (where can or could are possible), you have to use was/were able to do smth. or was/were capable of doing smth.

2. Could is not always the past of can, sometimes it has a present or future meaning. Perfect infinitive after can or could in such cases shows that they refer to the past.

3. Passive and progressive infinitives after can or could are also possible in some cases.

Упражнение 1. Прочтите и переведите следующие предложения, обращая внимание на значение модального глагола can либо его эквиваленты и форму инфинитива после них:

1. You can end your program with ‘quit’ command. 2. The information from memory can be retrieved by CPU. 3. We will be able to correct the arrows in the program. 4. Couldn’t the transistors or other radio elements be joined together right inside the crystal? 5. Engineers could thus substitute program code words for hardware parts. 6. Couldn’t they have created this program by themselves? 7. The computer memory can be considered as consisting of a number of cells capable of storing binary patterns representing program instructions or data. 8. He wasn’t able to perform those calculations without a computer. 9. In one program run, memory cells 5 and 6 could have been set to 70 and 25, respectively. 10. The sequence couldn’t have been chosen wrongly.