Do you know we have much difficulty ____

国际联运中，1张客票的有效期延长不得超过（）。

A.1次

B.2次

C.3次

D.4次

John received an invitation to dinner, and with his work ____, he gladly accepted it. [ ]

A. finished

B. finishing

C. having finished

D. was finished

具有凉血止血作用的药物是（）

A.大蓟

B.小蓟

C.地榆

D.槐花

E.侧柏叶

读图，并完成下列问题：写出图中字母所代表板块的名称：

A______B______

D______E______．

“黄河之水天上来，奔流到海不复回．”这“天上”是指（　　）

A．唐古拉山

B．祁连山

C．巴颜喀拉山

D．阿尔金山