形近字组词。
援（ ）键（ ）湍（ ）钧（ ）
缓（ ）健（ ）端（ ）均（ ）
援助 缓缓 键盘 健康 湍急 端正 千钧一发 平均
（答案不唯一）
The father and the son entered the tiger area _______ two doors were open at the time.
Suddenly five tigers appeared, one of which killed the father.
A．there
B．which
C．its
D．whose
