since then后面加什么时态？急啊

Question

Eg.
Scientists __________ (build) a station at the South Pole several yearsago. Since then they
________________ (get) muchinformation about the South Pole.怎么填？

Answer 1

since then 表示从那时起，从此以后，所以前面的主语应该是现在完成时或者过去式，后面的从句+一般完成时态
Scientists ___built____ (build) a station at the South Pole several yearsago. Since then they
____have got_____ (get) muchinformation about the South Pole.

希望对你有帮助哦~

Answer 2

用built，表示过去式，several years ago是明显的过去时标志；
用have got,表示过去完成时，Since then作为标志！本回答被提问者采纳

Answer 3

built....have got
since+过去时间点或since+一般过去时从句，主句用现在完成时

Answer 4

built
had got
若干年以前 当然用一般过去式，但自从他们get muchinformation明显发生在build a station之前，并且真是因为他们get nuchinformation才会build astation.所以用过去完成时。