16、 A dark suit is__________ to a light one for evening wear.

　　A.fayorable

　　B.suitable

　　C.preferable

　　D.proper

　　17、 Professor Smith is said__________another important discovery in chemistry.

　　A.to make

　　B.to have made

　　C.having being made

　　D.having made

　　18、 So far as is known，the original manuscripts of Shakespeare’s plays are no longer in__________ .

　　A.evidence

　　B.presence

　　C.absence

　　D.existence

　　19、 __________ many people prefer coffee，he drinks tea as usual.

　　A.While

　　B.Besides

　　C.Because of

　　D.Except

　　20、 The heavy snow in early spring may__________the growth of the wheat.

　　A.hold on

　　B.hold up

　　C.hold out

　　D.hold in