____ the morning of my mother’s birthday, I usually help my mother do some housework.
| A．In | B．At | C．During | D．On |
He made three good friends in the university, ______ joined the army after graduation.
| A．one of them | B．one of whom | C．one | D．one of which |
_______ is certain, people’s living conditions in China have improved a lot since the 1980s.
| A．It | B．As | C．what | D．Which |
Humans are polluting the earth day by day, ________, of course, will cause punishment sooner or later.
| A．that | B．it | C．which | D．what |
You’d better cut your hair short. Our school doesn’t _______long hair.
| A．approve of students wore | B．approve students to wear |
| C．approve of students to wear | D．approve of students wearing |
—When can we make an appointment with you , sir ?
—What about Wednesday afternoon ?
—OK．_______
| A．Do you have time then ? | B．It doesn’t suit me． |
| C．That’s settled． | D．It’s so nice to meet you． |