________ do you go to visit your grandparents–Less than three times a month.

In those days John with his classmates _____ kept busy preparing for the exam.

The book is very good, but I don’t have money (钱).—You can ______ your mother ______ some money.

Do you have a penI want _____ a letter.

(2013·辽宁六校高三联考)Have you ever seen any trees ________ leaves were black because of the polluted air?