這不是考查強調句嗎　　

請看下面一題，它是考查強調句式嗎？　　

It might have been John __________ bought a new book for Mary yesterday. 　　

A. what                        B. since                        C. that                        D. then 　　

此題應選 C。此題的難點在于考生看不出這是一個強調句型，因為主句的謂語動詞be采用了might have been這一復雜形式。此句若改為非強調句，則可以是：　　

John might have bought a new book for Mary yesterday. 約翰昨天可能給瑪麗買了一本新書。　　

將此句改為強調句(強調主語)，則可以有兩種形式：　　

a. It is John that might have bought a new book for Mary yesterday. 　　

b. It might have been John that bought a new book for Mary yesterday. 　　

又如：　　

It must be a girl that wrote the letter. 寫這封信的一定是個女孩。　　

It might be yesterday that he left for Beijing. 他可能是昨天去北京的。　　

Can it be Jim that has stolen the money? 偷錢的會是吉姆嗎?　　

It may be next week that he leaves for Paris. 他可能是下個星期去巴黎。　　

It might have been her boyfriend that bought so nice a handbag for her. 給她買那樣好看一個手提包的可能是她的男朋友。