选择下列单词或词组填入每句的空格中。每空格限填—词，每词只能填—次。

A．bad

B．Perhaps

C．outdoor activity    

D．practise swimming   

E．in spring

F．careful
（1）Running is Mark's favourite ________.
（2）Susan had a ________ cold. She went to see a doctor.   
（3）________ my son will be an astronaut in the future.   
（4）We ________ three times a week.   
（5）It's a good idea to have a picnic ________.   
（6）In London, traffic keeps to the left, so you should be ________.