干眼症的主要临床表现
A．易疲劳，眼部不适B．畏光、视物模糊C．干涩异物感D．不能耐受烟尘E．以上全是
参考答案：E
— ______ do you go to the old people's house, Tom?
— Once a month. [ ]
A. How long
B. How far
C. How soon
D. How often
表达式1+2+"hello"+8的值为( )。
A．"12hello8"
B．"3hello8"
C．12hello
D．不能运算
