下列长城沿线主要旅游景点中，位于河北省的有( )。
A．山海关
B．古北口
C．黄崖关
D．居庸关
E．金山岭
参考答案：A,B,E
— How can we finish the task in such a short time?
— Don't be worried. There ______ willing helpers. [ ]
A. were not lack of
B. are no short of
C. was no short of
D. is no lack of
动机有激活、______和强化三个基本功能。
