问题：
It"s exciting to be a chairperson, but I"m________ my ability to do all the extra work.
[ ]
A. looking about
B. learning about
C. quarrelling about
D. worried about
It"s exciting to be a chairperson, but I"m________ my ability to do all the extra work.
B. learning about
C. quarrelling about
D. worried about
[ ]
A. looking about B. learning about
C. quarrelling about
D. worried about
参考答案：