补全对话：根据上下文意思在下面对话的空格中填上适当的词，将对话补充完整。
A: Hello! _____________________________________?
B: I like spring best.
A: _________________________________?
B: Because I can plant trees. __________________________?
A: I like summer best.
B: _______________________________ in summer?
A: I usually climb mountains in summer.
B: Can you swim in the lake?
A: No, ___________.