`1.` It's( took) them (at least) two month (learning) how (to pronuonce) these world
- Đáp án: C. learning
- Sửa: learning `->` to learn ( cấu trúc at least + to V )
`2.` Lake superior , (that) ( Lies on ) the US Canadian border , is the ( Largest Lake ) (in) America
- Đáp án: A: that
- Sửa: that `->` which ( đại từ quan hệ thay thế cho danh từ " Lake superior " )
`text{Good luck !}`