单项选择题
A.5% B.10% C.15% D.20%
A.≥1.5 B.≥ 2.5 C.≥3.5 D.≥4.5
A.旋塞 B.闸 C.截止 D.隔膜
A.0.01 B.0.1 C.1 D.10
微信扫一扫,加关注免费搜题