I. Underline the correct form. (10.6B MLH) 1. When Anne opened / had opened the door, she realized that somebody broke / had broken into. 2. He couldn’t make a sandwich because he forgot / had forgotten to buy bread. 3. Clyde Tombaugh discovered / had discovered the planet Pluto in 1930. 4. By the time Julia left / had left the shop, she spent / had spent all her money on clothes. 5. I didn’t want/ hadn’t wanted to see that film because I saw / had seen it twice. 6. Philip tidied / had tidied his bedroom before he left / had left for work.

1. When Anne opened / had opened the door, she realized that somebody broke / had broken into.

Giải thích : 'Anne opened the door' xảy ra trước nên dùng thì quá khứ đơn, vế sau dùng quá khứ hoàn thành.

2. He couldn’t make a sandwich because he forgot / had forgotten to buy bread.

Giải thích : 'He forgot to but bread' xảy ra trước nên dùng thì quá khứ đơn, vế sau dùng quá khứ hoàn thành.

3. Clyde Tombaugh discovered / had discovered the planet Pluto in 1930.

Giải thích : 'in 1930' là một thời gian cụ thể trong quá khứ -> quá khứ đơn

4. By the time Julia left / had left the shop, she spent / had spent all her money on clothes.

Giải thích : 'By the time Julia left the shop' xảy ra trước nên dùng thì quá khứ đơn, vế sau dùng quá khứ hoàn thành.

5. I didn’t want/ hadn’t wanted to see that film because I saw / had seen it twice.

Giải thích : Vế trước điền thì quá khứ đơn, vế sau điền quá khứ hoàn thành vì đó là khoảng thời gian trước một sự việc trong quá khứ.

6. Philip tidied / had tidied his bedroom before he left / had left for work.

Giải thích : Vế trước điền thì quá khứ hoàn thành vì đó là khoảng thời gian trước một sự việc trong quá khứ. , vế sau điền quá khứ đơn