MessageDate 8 May 2005To Rupert GrintFrom Patrick Fisher, (1) DepartmentMessageMr, Fisher has received an (2) in Colin Co.He wants to discuss about his (3) .He has to reply by (4) . 1（）

MessageDate 8 May 2005To Rupert GrintFrom Patrick Fisher, (1) DepartmentMessageMr, Fisher has received an (2) in Colin Co.He wants to discuss about his (3) .He has to reply by (4) . 4（）

MessageDate 8 May 2005To Rupert GrintFrom Patrick Fisher, (1) DepartmentMessageMr, Fisher has received an (2) in Colin Co.He wants to discuss about his (3) .He has to reply by (4) . 3（）

MessageDate 8 May 2005To Rupert GrintFrom Patrick Fisher, (1) DepartmentMessageMr, Fisher has received an (2) in Colin Co.He wants to discuss about his (3) .He has to reply by (4) . 2（）

现代地球大气的主要成分是 。 A: H2、He、CO B: CO、CO2、H2O C: CH4、O2 D: N2、O2 E: NH3、H2O

扩散速度二倍于CH4的气体是（） A: He B: H C: CO

TIG焊焊接铜时，采用那些气体可增加熔深？（） A: Ar B: Ar+25%He C: Ar+2%CO D: Ar+75%He

以下气体属于活性气体的是（） A: O B: CO C: Ar D: He

ECD的载气种类一般有哪些（）。 A: N2 B: H2 C: He D: CO

扩散速率三倍于水蒸气的气体是（） A: He B: H C: CO D: CH