201×7强碱性苯乙烯系阴离子交换树脂的湿真密度一般在()g/ml
A.0.30~0.35
B.1.60~1.11
C.5.60~5.70
D.7.80~8.00
参考答案:B
The teacher and inventor________ from Germany.
A.is
B.are
C.were
D.come
粘胶短纤无纺织物制外科手术服