I’m very glad to see that your vocabulary is gradually .A. building upB. turning upC. comi

问题补充：

I’m very glad to see that your vocabulary is gradually .

A. building up

B. turning up

C. coming up

D. waking up

答案：

(答案→)A. building up

B. turning up

C. coming up

D. waking up

解析：本题的含义是我很高兴看到你的词汇量逐步地在增多，build up表示此意，故本题选A。