I had not only made a mistake but alsohad criticized his work as well.
或:Not only had I made a mistake,but also I had criticized his work.
not only ...but also 在连接谓语时可放在助动词后,行为动词前
在连接句子时,放在句首,但请注意放在句首要倒装,也就是把助动词移到主语前.but also后 不要倒装.如上例句
not only ...but also 连接主语时就放在主语前,注意主谓一致.要就近原则.
如: Not only I but also he is fond of English.
Not only he but also I am fond of English.
以此类推,连接宾语就放在宾语前.我就不举例了.