Tom is very happy in China during this period because his Chinese every day.
A. has improved
B. is improving
C. improved
D. is improved
网友回答
A. has improved
(答案→)B. is improving
C. improved
D. is improved
解析：考查动词时态。句意：在中国的这段日子Tom很高兴，因为他的汉语水平天天在提高。用现在进行时表示现阶段正在进行的动作。