短日照处理方法为每天光照时间控制在（）小时以下。
参考答案：10
四肢手术折线时间为
A．4～5天B．6～7天C．7～9天D．10～12天E．14天
The research mainly deals with the difficulty the students have ______ their attention pm their study all the time.
A．to focus
B．to be focused
C．focusing
D．focused
