A.≤0.3% B.≤0.5% C.≤1.0% D.根據(jù)控制指標(biāo)
A.≤0.1% B.≤0.5% C.≤1.0% D.根據(jù)控制指標(biāo)
A.反丁烯-2 B.順丁烯-2 C.丁二烯-1.3 D.乙烯基乙炔