The camera was okay, _________ not my nose.[ ]
A. but
B. and
C. or
D. too
答案:A
我国的历史古迹长城总长约6700000米,用科学记数法来表示( );
酸发酵法是利用乳酸菌和醋酸菌等发酵产酸,以防止食物腐败。( )