1.Not only --- her how to do it ,but offered to help her as

第一题选A.否定词位于句首,要用部分倒装.一般说来,以下否定词位于句首,句子要用倒装（部分倒装——用一般问句的形式）：seldom,never,little,few,hard－ ly,not,not until,in vain,in no way,by no means,on no ac- count,no longer 等：
Never does he come late．他从不迟到.
本题中Not only 后应跟助动词,然后才是主语加动词原型
第二题：
I’m sorry to keep you waiting me so long.