________ the prices and functions of different types of computers before you make up your mind which to buy.
| A．To compare | B．Comparing | C．Compared | D．Compare |
The Romany are thought _______ from India.
| A．to have come | B．to come |
| C．to coming | D．to be coming |
—Haven’t seen you for ages! Where have you been?
—I went to Ning Xia and _______ there for a year, teaching as a volunteer.
| A．stayed | B．stay |
| C．had stayed | D．am staying |
Can you tell me ________ makes the video Gagman Style so popular?
| A．what is it that | B．how is it that |
| C．what it is that | D．how it is that |
After the strong typhoon “Haiyan” visited Philippines, gone ________ the beauty and many other things.
| A．is | B．was | C．are | D．were |
There are three main classes of drugs, ________ has a different effect on the body.
| A．each of them | B．all of them |
| C．each of which | D．all of which |