注射杜冷丁可以造成婴儿呼吸抑制
A．卵子受精后14天内B．妊娠3-12周C．妊娠4个月至分娩D．分娩期E．哺乳期
参考答案：D
Jim talked for about half an hour yesterday.Never＿＿＿＿＿ him talk so much.
A．I heard
B．did I hear
C．I had heard
D．had I heard
气体分馏装置停车系统若不抽残液，则会对火炬系统造成冲击，同时也浪费了资源。
