My friend has returned from the UK. She ______ at Oxford for four years, during which we communicated with each other on the Internet.

A. studied           B. has studied                    C. had studied          D. has been studying

All the clothes donated by the citizens need cleaning thoroughly before being sent to the earth-stricken area, ______ ?

A. needn’t they                    B. don’t they                      C. didn’t they            D. shouldn’t they

Believe it or not, crying is a way you can imagine ______ pressure.

A. relieving                            B. to relieve                       C. relieved                 D. relieve

Storm chasing is so dangerous that some chasers are often hurt in accidents ______ by driving in a heavy rain.

A. having caused                 B. caused                           C. to be caused        D. causing

______ Chief Engineer, as his family had expected, made his father happy and proud.

A. Mike being appointed                  B. Mike’s appointed

C. Mike appointing                            D. Mike’s being appointed

The growing speed of a plant is influenced by a number of factors, ______ are beyond our control.

A. most of them                            B. most of what                 C. most of which      D. most of that

The most widely accepted theory about the beginning of drama is based on the concept ______ drama evolved from ritual.

A. which                                 B. that                                  C. when                      D. as

______ sweet, this type of flower sells the best in the market.

A. Smelt                                 B. Being smelt                   C. To smell                 D. Smelling

Having mastered the technologies of manned spacecraft, China became the third country in the world ______ manned spaceflight independently.

A. develop                             B. to develop                      C. developing            D. developed

______ bears’ number has increased, their conflicts with local people have increased too.

A. If                                         B. With                                 C. As                            D. While