上消化道出血止血可选用（）
A．肾上腺素
B．去甲肾上腺素
C．异丙肾上腺素
D．多巴胺
E．麻黄碱
参考答案：B
The scientists approached the pandas quietly and watched them. The underlined part means ____. [ ]
A. left behind
B. ran quickly to
C. went off
D. came near to
以下各组中属于替代品的是( )。
A．核能和太阳能
B．家用电器和电
C．汽车和汽油
D．电力和煤气
E．网球和网球拍
