阻止嘧啶类核苷酸形成的药物是()
A.环磷酰胺
B.顺铂
C.氟尿嘧啶
D.巯嘌呤
E.甲氨蝶呤
参考答案:C
—Did you have a good weekend?
—________. I was busy studying for the test. [ ]
A. Sure
B. I think so
C. I am afraid not
D. I hope not
第29届奥运会在中国北京成功举行,吸引了许多国内外的游客.这一年的二月份有29天.______.