Water always boils when you heat it long enough.

Water always boils when you heat it long enough.
A. If heated long enough, water boils.
B. If water is heated long enough, it boils.
C. If you heat water long enough, it boils.
D. All are correct.

Đáp án: D
Dịch: Nước luôn sôi khi bạn đun nóng đủ lâu.