If I ........................ you were sick. I would have called sooner.

A. knew

B. had known

C. know

D. would have known

Số thích hợp điền vào chỗ chấm để  3km 15 m  = …………km là:

A. 3,15 km

B. 31,5 km

C. 3,015 km

D. 30,15 km