病毒持续感染属于
A.免疫防御
B.免疫自稳
C.免疫监视功能失调
D.免疫自稳功能失调
E.免疫防御作用过高
参考答案:C
The factory_____I worked last year is just the one I visited yesterday.
A.which
B.where
C.that
D.who
某航道上有一桥梁,标注高度15m,已知该地大潮升3.2m,小潮升1.0m,平均海面280cm,0800潮高0.5m,则当时桥梁的实际高度为()。
A.18.7m
B.17.3m
C.17.7m
D.18.3m