1. It is said that this is an ilness that can result in total blindness_1eft untreated.
A. after
B. if
C. since
D. unless
2.一Dear me! I've been in America for more than three weeks.
_you are settled, why don't you take up some serious study?
A. If
B. After
C. Now that
D. Even if
3_international commerce grows, there is an amazing development which is expanding at ever-increasing rate-business on the internet.
A.As .
B. Since
C. With
D. While
4. Please take a hat with you_the sun is very hot.
A. in the case
B. in case
C. in case of
D. in the case of
5. You may borrow this book_you prormise to give it back.
A. asif
B. unless
C. as long as
D. even if
6. It must have rained last night,_the roads are wet this morning .
A. as
B. for .
C. because
D. since
[答案与解析]
1. B. ifleft untreated可看作是条件状语从句if it is left untreated的省略。句意为“据说这种疾病如不治，会导致完全看不见。”
2.C。根据上句“天啊!我来美国已经三星期多了。”可推知下句“既然你已安顿下来，为什么不开始认真学习呢?”nowthat意为“既然”符合句意。故答案为B。.
3.A。句意为“随着国际商务的扩大，因特网上的业务正日益加速取得了惊人的发展。”as意为“随着”，引导从句; with为介词，意为“随着”，但不能引导从句。
4.B。incaseof意为“如果，万一”，如: In case of rain they canltgo.万一下雨，他们就不能去了。incase意为 “以防，可能;倘若”;句意为“倘若太阳很利害，你就把帽子戴上。”
5.C。as longas表示条件，意为“只要”。句意为“只要你答应归还，你就可以把这书借走。”
6.B。for是并列连词，表示的原因往往是按照逻辑推断出来的。后一分句“今天早上路上是潮湿的”是为前一-分句中做出的判断“昨晚准是下雨了”进行解释，而不是造成这一判断的直 接原因，故答案为B。
