The pleasant smell makes me _____ hungry.[ ]
A. to feel
B. feeling
C. feels
D. feel
答案:D
There is no time _______ the box now.
[ ]
A. open
B. opening
C. opens
D. to open
生物圈中的碳-氧平衡是大气中的______和______的含量保持______的状态.