问题补充:
In such dry weather, the flowers will have to be watered if they
A. have survived
B. are to survive
C. would survive
D. will survive
答案:
A. have survived
(答案→)B. are to survive
C. would survive
D. will survive
解析:此句的主句是将来时,条件状语从句要用一般现在时表示将来时。if they are to survive表示“如果它们要活下来”。