Question

单项选择题，求教大神们

单项选择题，求教大神们It's a good time__A___in spring. Many people enjoy it.
A. for flying kites
为什么用介词“for”?
而It's a good time__B___in fall.
B. to climb hills
为什么选介词“to”?

Answer 1

It's a good time for flying kites in spring. Many people enjoy it.
A. 为什么用介词“for”?
而It's a good time to climb hills in fall.
B. 为什么选介词“to”?
第一句因为后边的动词是ing形式所以用for,
第二句 因为动词是原形，所以用to。 to do是不定式。to不是介词，是不定式符号（小品词）

Answer 2

It's time有两种用法：It's time for sth(名词或名词性短语)；It's time to do(原形) sth.
It's a good time__A___in spring. Many people enjoy it.
A. for flying kites
It's a good time__B___in fall.
B. to climb hills
正好是上述两种用法的例子，都是正确的。