In such hot weather the new plant will have to be protected from the sun if they . A. ar

问题补充：

In such hot weather, the new plant will have to be protected from the sun if they .

A. are surviving

B. survives

C. are to survive

D. have survived

答案：

A. are surviving

B. survives

(答案→)C. are to survive

D. have survived

解析：考查时态。be to do 表示将来，注定会发生，句意：在如此炎热的天气中，如果这些植物一定要生存的话这种新植物将要被保护免受阳光的照射。所以选C。