一變：肯定句變為否定句
【技巧1】當句中含有情態動詞或助動詞could，would，should等時，可直接在其後面加not構成否定句。例如：
I could get you a concert ticket。 I could not / couldnt get you a concert ticket。
【技巧2】當句中含有系動詞was，were 時，可直接在其後加not構成否定句。例如：
I was on the Internet when you called me。 I was not / wasnt on the Internet when you called me。
【技巧3】當句中謂語是除情態動詞、助動詞、系動詞was，were以外的'動詞時，在該動詞之前加did not / didnt，動詞還原，構成否定句。例如：
The famous singer sang some Chinese songs。 The famous singer did not / didnt sing any Chinese songs。
二變：陳述句變為一般疑問句
【技巧1】移動詞語的位置。將was，were，could，would，should等移到句首。例如：
He could pack his things himself。 Could he pack his things himself？
【技巧2】新增助動詞did。謂語是除情態動詞、助動詞、系動詞was，were以外的動詞時，在主語之前加did，動詞還原。例如：
Mr Li looked very old。 Did Mr Li look very old？
三變：陳述句變為特殊疑問句
【技巧1】確定疑問詞：人who / whom，物what，地點where，時間when / what time，原因why，頻率how often，長度how long，距離how far等等。例如：
They gave the concert last night。 When did they give the concert？
【技巧2】辨認結構形式：疑問詞+情態動詞/助動詞/ was / were / did +主語+。？ 例如：
The accident happened near the station。 Where did the accident happen
