为减少局麻药的吸收,常添加肾上腺素,浓度为()
A.1:200万
B.1:20万
C.1:2万
D.1:0.2万
E.1:50万
参考答案:B
选择填空。
I read the book yesterday, but I ______ enjoy it. [ ]
A.don't
B.didn't
C.wasn't
D.isn't