下列那一种因素容易增加棉被上细菌的数量 [ ]

A．关紧卧室的窗户

B．在太阳下晒

C．用开水煮

D．用有杀菌成分的洗衣粉洗涤

Today is Children's Day. There are lots of people inHappy Valley. It's very ______ .[ ]

A. busy        

B. uncrowned

C. hot          

D. crowded