植物细胞中最重要的二糖和多糖分别是
①乳糖和葡萄糖 ②蔗糖和麦芽糖 ③乳糖和麦芽糖 ④糖元和纤维素 ⑤植物淀粉和纤维素 [ ]
A.①④
B.②⑤
C.③④
D.③⑤
答案:B
Even though it is at least 20 years _____ we got to know, I can’t forget the scene_____ we were introduced to each other.
A.that , where
B.when, in which
C.since , when
D.since, where
下列哪项不属于弓形虫病易感人群()
A.肿瘤病人
B.艾滋病病人
C.高龄产妇
D.动物饲养员
E.常接受血液制品或输血者