-22等于( )
A.4
B.-4
C.-2
D.2
-22=-4.
故选B.
酯类药物易产生()。
A、水解反应
B、聚合反应
C、氧化反应
D、变旋反应
—______?
—Nothing serious,but a bit tired.
—Better have a rest now, dear.[ ]
A. Is that all
B. Is there anything else
C. What's this
D. What's the matter with you