求高手解决几道关于时态的题

1. B. had done; 过去完成时才合语法，参照之前的时态 I was going to ... 比那更早就完成啦 。
2. were selling; walked through 时 那些人正在卖，配合 walked、studied、bought 用过去进行时
3. D. have been shopping; 表示一直持续进行，直到说话的那刻。
4. have been; ... for months 忙了好几个月，直到去beach 都还没结束，只是休息一下。
5. should have been; since 前面基本都用完成式
6. has been going; 又见 since 而且仍在继续中所以完成进行式
7. did; 过去固定都从事的工作 - 煮饭
8. saved; 因为 up to now 的关系，简单陈述到目前为止的事实
9. had taken; 从后面那 might have arrived 得知这句需要用假设语气，过去完成式。
10. have been sick; 最近经常生病
11. are being built; 进行式+被动语态
12. were expected; 过去式+被动语态
13. finish; 结束（现在在做）的计划，跟在not until 之后通常都原形
14. have been working; ... for hours 已经在进行了，而且还没完

希望对您的学习和理解能有些帮助！

B ,sell , D , has been , shall , has gone, has been doing,had taken ,A,are building,had expected,
finish have been working