The defense works ______ long ago to keep the enemy away.
A: were built
B: has been built
C: had been built
D: was built
A: were built
B: has been built
C: had been built
D: was built
举一反三
- The defense works ______ built long ago to keep the enemy away. A: were B: has been C: had been D: was
- The defence works ____built long ago to keep the enemy away.
- Many factories________in the past three years. A: were built B: had built C: had been built D: have been built
- All of those houses _______ in the past ten years． A: were built B: had been built C: have been built D: have built
- Most of the houses _______ this year. A: has built B: have built C: has been built D: have been built