A person did studies of a subject or a theme and he writes a book or an article as the result or conclusion of his research. How would you express this in proper English? Thanks.

I haven't heare from him in a long time. If I want to say that "he has been busy in the period of time referred in the sentence", what would be the expression? Thanks.

The exercise specified that only one of them is correct. I throught that may have been was correct because it gives a sense of continuation from the past. But on the other way, may be is also correct. It refers to the present, and by the time I

I haven't heard from him for a long time. He may be /may have been busy. Which is the correct verb? Thanks.

I haven't heard from him for a long time. He may be/may have been busy . Which verb is correct? Thanks for your opinion.

I'd like to know too. Are "half the commuters surveyed..." and "half of the commuters surveyed..." correct? Are they interchangeable? Thanks.

The course will start in /during May. It became popular in /during the 1970s. Are all the prepositions correct with the verbs "start" and "become"? Thanks a lot.

thanks. I's like to know how "all people" and "all the people" are different. Does "all the people" refer to a specific number of people?

David told Nancy (that) Bill was at home. Is "that" a must? Thanks.

thanks. I asked a wrong question. I meant if "of" can be omitted. What is the difference between "all the people" and "all people"? Why can't we say "half people" ?