There were many ________ there.[ ]
A. backpacks
B. backpack
C. a backpack
答案:A
如果a、b的最大公因数是8,那么a和b的公因数有[ ]
A.2个
B.3个
C.4个
D.5个
有一种比狗更善于辨别气味的昆虫,最近被美国利用来反恐。它是:()
A.蝴蝶
B.晴蜒
C.蜜蜂
D.苍蝇