сделайте стопроцентно, последнее задание необязательно

I. 1. Helen has not come back from the University yet.
2. Were any of you...
3. has been increasing
4. burnt, conducted, has not finished the work yet
5. began, have completed
6. were taking
7. was, had defended
II. 1. What were my friends involved in?
2. Where have just these scientists returned from?
3. Which text had they translated by 1 o'clock?
4. When were the engeneers installing the equipment?
III. became, ate, fell, gave, spoke, wrote, saw, went, drank, flew
IV. Have you ever been to London? - Yes, I have. A few times. When were you there last time?
Did Michael Faraday make all his great discoveris in the mid of 18th or 19th century?
When the professor came to the laboratory, some of the students were still doing experiments, and some of them had already done the work.
Before the young scientiest did the experiment, he had done a hard work.
My groupmates has been very busy lately, as they have been preparing for examination, but they took their last test yesterday.