He approached the house. Then the policeman stopped him.

50/50

He approached the house.Then the policeman stoppedhim.

No sooner had he approached the house than the policeman stoppedhim.

Hardly had he approached the house than the policeman stoppedhim.

Had he not approached the house, the policeman would have stoppedhim.

Before he approached the house, the policeman had stoppedhim.

Giải thích

B. Sai cấu trúc: Hardly had S Vp2 when S Vqkd

C. Đây là mối quan hệ về thời gian, không phải mối quan hệ nguyên nhân, hệ quẩ nên không chuyển thành câu đk được

D. Sai trật tự của hành động