2019年mpa考试英语真题——动词的时态5

{01}He is so determined!He ________ on the problem for two hours, and he will go on with it until he works it out．
A.works
B.worked
C.is working
D.has been working
解析：
本题选D。
{02}The moment Jenny got home, she noticed a woman waiting for her．She ________ her before．
A.never saw
B.had never seen
C.never sees
D.has never seen
解析：
本题选B。
{03}He is so determined!He ________ on the problem for two hours, and he will go on with it until he works it out．
A.works
B.worked
C.is working
D.has been working
解析：
本题选D。