【单选题】
<img src=https://huaweicloudobs.ahjxjy.cn/E033CFC8AC09E7063F798447EEB03B1E.png title=10.png alt=10.png/>
①
<img src=https://huaweicloudobs.ahjxjy.cn/0C86ECE6C2352604907310221C48927D.png title=10-1.png alt=10-1.png/>
②
<img src=https://huaweicloudobs.ahjxjy.cn/3FBCFD8D09983D324E1E81A28CDD6565.png title=10-2.png alt=10-2.png/>
③
<img src=https://huaweicloudobs.ahjxjy.cn/97A2F7C078A01380DC051A9506552571.png title=10-3.png alt=10-3.png/>
④
<img src=https://huaweicloudobs.ahjxjy.cn/A856AFCB8BB94168F695FD41A227B598.png title=10-4.png alt=10-4.png/>
【单选题】
<img src=https://huaweicloudobs.ahjxjy.cn/0EFD2D062C1DA88B2F31B8C4A9CC6C31.png title=3.png alt=3.png/>
①
<img src=https://huaweicloudobs.ahjxjy.cn/07CDBA02B64FBC5BC81FC14AE89DF625.png title=3-1.png alt=3-1.png/>
②
<img src=https://huaweicloudobs.ahjxjy.cn/86082B73F7D07D2C830738DD21117951.png title=3-2.png alt=3-2.png/>
③
<img src=https://huaweicloudobs.ahjxjy.cn/7B9C8FD8868288389D04B3CB64BC0F54.png title=3-3.png alt=3-3.png/>
④
<img src=https://huaweicloudobs.ahjxjy.cn/71BA3C8646846C26F4B5A4B0A91ED7EF.png title=3-4.png alt=3-4.png/>
【单选题】
<img src=https://huaweicloudobs.ahjxjy.cn/819172A090D926AF927FAFB724387F88.png title=12.png alt=12.png/>
①
<img src=https://huaweicloudobs.ahjxjy.cn/D801891324866BC2864186D9F2919692.png title=12-1.png alt=12-1.png/>
②
<img src=https://huaweicloudobs.ahjxjy.cn/0075307DE09A54524E87CC1DA8C0342C.png title=12-2.png alt=12-2.png/>
③
<img src=https://huaweicloudobs.ahjxjy.cn/6F04D6EE8E3988D53917829A64A8EC90.png title=12-3.png alt=12-3.png/>
④
<img src=https://huaweicloudobs.ahjxjy.cn/A9E6D5AAFE79AF213CC5E3064F0EBE46.png title=12-4.png alt=12-4.png/>
【单选题】
<img src=https://huaweicloudobs.ahjxjy.cn/653AFBC236AB5A1DB7FDDDBA6818DAF7.png title=19.png alt=19.png/>
①
<img src=https://huaweicloudobs.ahjxjy.cn/DBF1C6E509BD60C0EF7F49C0B377B993.png title=19-1.png alt=19-1.png/>
②
<img src=https://huaweicloudobs.ahjxjy.cn/A377CBD27BED86A5669C686C2626B241.png title=19-2.png alt=19-2.png/>
③
<img src=https://huaweicloudobs.ahjxjy.cn/BE18999568BB15554EBEA520B374A89C.png title=19-3.png alt=19-3.png/>
④
<img src=https://huaweicloudobs.ahjxjy.cn/1E4D7E87E6F69603BBE317B2D4226E4B.png title=19-4.png alt=19-4.png/>
【单选题】
<img src=https://huaweicloudobs.ahjxjy.cn/179D629E5634CBD3401D702FB96699FA.png title=5.png alt=5.png/>
①
<img src=https://huaweicloudobs.ahjxjy.cn/0C67101837C7694B4A3D364E0D953684.png title=5-1.png alt=5-1.png/>
②
<img src=https://huaweicloudobs.ahjxjy.cn/BD33730BAF577C63A631DB1F45A99F0F.png title=5-2.png alt=5-2.png/>
③
<img src=https://huaweicloudobs.ahjxjy.cn/903B2735CA9282AF591719D0F9D05882.png title=5-3.png alt=5-3.png/>
④
<img src=https://huaweicloudobs.ahjxjy.cn/F7EFC8540F6F6D42E5FE939840714D90.png title=5-4.png alt=5-4.png/>
【单选题】
<img src=https://huaweicloudobs.ahjxjy.cn/CD69F794AB10315027C80A71D6F62566.png title=18.png alt=18.png/>
①
<img src=https://huaweicloudobs.ahjxjy.cn/D3303181AC9E1903F89DEEF078BCF559.png title=18-1.png alt=18-1.png/>
②
<img src=https://huaweicloudobs.ahjxjy.cn/3931FFF2F04214EE1B6AA03C0CA9F954.png title=18-2.png alt=18-2.png/>
③
<img src=https://huaweicloudobs.ahjxjy.cn/F40594E034A219F5F9BD917AD1E949FF.png title=18-3.png alt=18-3.png/>
④
<img src=https://huaweicloudobs.ahjxjy.cn/B27B356A7FD63B30B724F029AD492471.png title=18-4.png alt=18-4.png/>
【单选题】
<img src=https://huaweicloudobs.ahjxjy.cn/14C847A29057ECE451B8C438A50801F8.png title=7.png alt=7.png/>
①
<img src=https://huaweicloudobs.ahjxjy.cn/2AB2D636D6035A6B07B537DDE6EB9B42.png title=7-1.png alt=7-1.png/>
②
<img src=https://huaweicloudobs.ahjxjy.cn/1779F4BDBB5FC9D3FA94B49E3BD0BAE5.png title=7-2.png alt=7-2.png/>
③
<img src=https://huaweicloudobs.ahjxjy.cn/48895213C024E2941DD103B860ACBC24.png title=7-3.png alt=7-3.png/>
④
<img src=https://huaweicloudobs.ahjxjy.cn/01239642C02FD159D3F89A7F207EAA43.png title=7-4.png alt=7-4.png/>
【判断题】
钢铁含碳量越高,越容易焊得优质接头;相同的含碳量,合金钢的焊接性更。