下面是关于史密斯一家郊游的3对句子。每对句子中，每一句是原句，第二句是对第一句的改写。
要求根据原句和第二句中已经给出的部分用一至五个单词补全第二句，注意不能改变原句的意思。
At first Tom found it difficult to play table tennis.
At first Tom found that ______ difficult to play table tennis.

A．Spring.
B．Summer.
C．Winter.

A．They are talking about the man’s vacation.
B．They are talking about their vacation plans.
C．They are talking about the weather.