313.I was really anxious about you .You____home without a word.

A.mustn't leave 　 B.shouldn't have left　　　　 C.couldn't have left 　　 leave

312.Visitors______not to touch the exhibits.

　 A.will request 　　B.request　　　　　 C.are requesting 　　D.are requested

311.A computer can only do _____you have instructed it to do.

　A.how 　　B.after 　　C.what 　　　D.when

310.I______ping-pong quite well,but I haven't had time to play since the new year.

　A.will play 　　B.have played 　　C.played 　　D.play

309.The warmth of _______sweater will of couse be determined by the sort of _____wool used.

　A.the;the　　 B.the ;不填 　　C.不填;the 　　D.不填；不填

308.It is generally believed that teaching is _______it is a science.

A.an art much as 　B.much an art as　　　　　 C.as an art much as　D.as much an art as

307.The home inprovements have taken what little there is______my spare time .

A.from 　B.in　 C.of 　　D.at

306. We didn't plan our art exhibition like that but it ________very well.

　A.worked out 　B.tried out 　　C.went on 　　D.carried on

305.The Parkers bought a new house but________will need a lot of work before they can move in .

　A.they　　 B.it 　　C.one 　　D.which

304.Selecting a mobile phone for personal use is no easy task because technology__________so rapidly.

　A.is changing 　 B.has changed　　　　　 C.will have changed 　　D.will change