Before a problem can be solved, it must be obvious ______the problem itself is.
| A．what | B．that | C．which | D．why |
--- Who do you think ___ the book here?
--- It may be John. He was sitting here all the morning.
| A．was leaving | B．leaves | C．had left | D．has left |
David can speak idiomatic American English and yet, _____ English, he doesn't know it at all.
| A．how to teach | B．when it comes to teaching |
| C．when he teaches | D．however he teaches |
--- How I wish we studied ____ there are fewer exams!
--- You’re joking!
| A．where | B．in which | C．the place where | D．in where |
--- Could you introduce me a high quality car?
--- My pleasure. ____ well even on wet roads, this kind of car is very popular.
| A．Handled | B．To handle | C．Handling | D．Being handled |
--- Where are the students ? How could they keep us waiting for so long?
--- They started an hour ago and they____ be here in fifteen minutes, I think.
| A．might | B．would | C．should | D．must |