8. He said he would come, he didn't ______.
A.though
B.although
C.yet
D.Too
答案:A
微生物传感器快速测定法测定生化需氧量时,调节水样PH所用酸碱的量不应超过水样的0.5%。
()资源是第一资源。
A.人才
B.环境
C.社会