小题1:B
小题2:A
小题3:C
小题4:E
小题5:F
小题1:根据后面的回答I didn’t do well in the chemistry test可知，他在问原因
小题2:根据前面的 I could hardly believe you were not doing well in chemistry可知
小题3:根据后面的 I made some very stupid mistakes可知
小题4:根据语境
小题5:根据后面的I have certainly learned a lesson可知，此处是给予一定的建议