J23—100压力机的公称压力为（）。
A、100公斤
B、1000吨
C、1000千牛
参考答案：C
在致病性大肠埃希菌中，能引起痢疾样腹泻，病变类似志贺菌所致细菌性痢疾的是（）
A.EIEC
B.ETEC
C.EPEC
D.EHEC
E.EaggEC
We have received your letter of September 12，（）we are glad to know that you are interested in our electric heaters.
A.which
B.at which
C.from which
D.in which
