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。