Let's _____ the sports club. [ ]
A. do join
B. to join
C. join
D. joins
答案:C
Can you see the picture? Yes, . [ ]
A. I can
B. I am
C. I see
具有抗菌作用的是()
A.欧芹酚甲醚(奥斯脑)
B.七叶内酯
C.海棠果内酯
D.双香豆素
E.黄曲霉素