51._______ is known to all，China will be an _______ powerful country in 20 or 30 years‘ time.

　　A.That;advancing B.This;advanced C.As;advanced D.It;advancing

　　52.It rained hard yesterday， ______ prevented me from going to the park.

　　A. that B. which C. as D. it

　　53.When _______， water will be turned into steam.

　　A. heated B. heating C. being heat D. having heated

　　54.Please write a report _______ the above subjects are to be covered.

　　A. which B. in which C. that D. in that

　　55.This is the most beautiful village _______ I visited these years.

　　A. which B. where C. in which D. that

　　56._______， could you get me a Turkish conversation book?

　　A. In this way B. By the way C. In no way D. In any way

　　57.Such person _______ you describe is rare nowadays.

　　A.it B.as C.that D.what

　　58.The oceans do not so much divide the world _______ unite it.

　　A. as B. that C. but D. like

　　59.He found _______ difficult to study maths.

　　A. it B. that C. as D. too

　　60.I understood from her that you undertook other important work ______.

　　A. as well B. as too as C. as also as D. as good as