β受体阻断药的药理作用表现为（）
A.心率加快
B.血压升高
C.抑制脂肪分解
D.促进肾素分泌
E.心排血量增加
参考答案：C
She wanted to be independent of her parents. She tried ____ alone, but she didn’t like it and moved back home.
A．living
B．to live
C．to be living
D．having lived
调车手信号，昼间显示展开的黄色信号旗高举头上左右摇动，表示（）。
A.减速信号
B.道岔开通信号
C.机车出入段进路道岔准备妥当
D.引导手信号
