After he worked out the solution, _____ appeared a smile on his face。

A. Can’t have been B. mustn’t have been

C. shouldn’t have been D. wouldn’t have been

A. from B. in C. before D. into

A, originally B. extremely C. violently D. intensively

A. that B. what C. which D. all

A. taking off B. setting aside

C. getting along with D. putting out

A. trim B. improve C. refine D. repair

A. business B. purchase C. bargain D.sale

A. working B. works C. to work D. worked

A.ate more food and had more physical activities

B.ate less food but had more activities

C.ate less food and had less physical exercise

D.had more weight problems

A.Yes,there is plenty of evidence.

B.Of course,there is some evidence to show this is true.

C.There is hardly any scientific evidence to support this.

D.We don't know because the information is not given.