选词填空,把字母编号填在横线上。

A．play sports

B．Because

C．writing

D．swimming

E.climbing
(1)I like summer .__________I can swim in the lake .  
(2)He is __________an e-mail in the study .  
(3)I often ___________ .
(4)She is _________.
(5)What are they doing ? They are __________trees .