1.It _____ten years since he left the army .
A.is B.has C.will D. was
可另用"It is + 一时间+since从句"来表示，故应选A。
2. I______a letter from him since he left.
A. didn't receive B. haven't got C. didn't have D. haven't heard
解析：据since可知，应排除A、C，"hear from sb.=receive/get/have a letter from sb."意为"收到某人的来信"，故选B。
3.Both of them ________________ (be) in Hongkong for ten days.（用时态填空）
4.Our teacher has studied Japanese ______ three years.（用since和for填空）
5.My parents ______Shandong for ten years .
A.have been in B.have been to
C.have gone to D.have been
解析："have/has been to +地点"表示"曾经去过某地（但现在已不在那儿)。"故应为A
6.I wonder why Jenny ______ us recently. We should have heard from her by now.
A. hasn’t written B. doesn’t write
C. won’t write D. hadn’t written
解析：由 recently 和 by now 可知用现在完成时。故选A
7.—How long ______ David and Vicky ______ married?
—For about four years.
A. were; being B. have; got
C. have; been D. did; get
解析：由 For about four years 可知，要用现在完成时，排除 A 和 D; 与时间段连用，不可用 get married, 要用 be married。故选C