It was only after he had read the papers Mr. Gross realized the task Before him was extremely difficult to complete.
| A．when | B．that | C．which | D．What |
_______ 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． |
The Internet is regarded as one of the reasons_______ many people aren’t getting enough sleep now．
| A．which | B．what | C．as | D．why |