991.Tony,come down and help me with the heavy box!
Come on!I _______ all day long.Get Peter to do that!

A.work

B.had been working

C.had worked

D.have been working

992.Gina has a sweet tooth and loves meat more than anything else.
No wonder she _______ weight so fast.

A,gains

B.gained

C.had gained

D.is gaining

991.答案是D;

考查动词的时态在具体语境中的应用。根据语境和下文all day long暗示，另外此处主体语境是现在时，选D。

992.答案是D;

gain weight增加体重。根据上下文得知，由于爱吃甜食和肉，体重不断增加。