心绞痛发作时应立即选择哪种药物合适（）
A.洋地黄类药物
B.潘生丁
C.阿司匹林
D.硝酸甘油
E.消心痛
参考答案：D
D-4103、D-4104排出冷凝水分别进入C-4101的何处？
—Excuse me , Have you got an eraser?
—Sorry, I haven't. Why _____ you ask Mary? Perhaps she has one.[ ]
A. do
B. don't
C. did
D. didn't
