21． The experiment cannot be described as ________ failure; it's ________ experience that will lead to our future success.
A．a；an B．a; 不填
C．不填；an D．不填；不填
答案：A 考查冠词。句意：这个实验不能被说成是失败的事；它是通往未来成功的一次经历。failure失败的人或事，可数；experience经历，可数，故选A。
22．When Tom came back to life, he found himself ________ in the woods and everything he had ________.
A．lying; stolen B．lying; stealing
C．lay; stolen D．lay; stealing
答案：A 句意：当汤姆苏醒过来，他发现自己躺在树林中，而他的东西都被偷了。find的第一个宾语himself与lie之间为主谓关系，应用动词ing形式作宾语补足语；第二个宾语everything与steal之间为被动关系，应用动词ed形式作宾语补足语；he had为省略关系词的定语从句修饰everything。
23．Keep on trying and you'll be ________ at how much you can achieve one day.
A．confused B．bored
C．amused D．astonished
答案：D 考查形容词词义辨析。句意：不断努力，你总有一天会吃惊于你取得的成就。be astonished at...吃惊于……。
24． I have been seeking what I want all these years，but ________ I have achieved nothing.
A．until then B．up to now
C．from now on D．in the future
答案：B 考查短语辨析。句意：这些年来我一直在追求我想要的东西，但是至今一无所获。根据谓语的时态是现在完成时可判断选up to now“直到现在”。until then直到那时；from now on从现在起；in the future在将来。
