It is partly the summer day is longer that everything has a larger time to warm up.A. for

问题补充：

It is partly the summer day is longer that everything has a larger time to warm up.

A. for

B. that

C. the reason

D. because

答案：

@@A. for@@B. that@@C. the reason@@(答案)D. because

解析：强调句型中的原因状语从句只能用because引导。