back weld和backing weld区别在那里

back weld和backing weld区别在那里 weld he's heading back 和he's backing有什么区别?都有他正在回来的路上的意思 solder 和weld有什么区别? I will be back &I will be backing..正确的说法不是i will be backing吗?怎么阿诺来个i will be back俚语吗? Weld Quay和umbrella怎么读啊 求谐音 Butt Weld weld nipple weld,calc. backing singer backing vocals backing board backing是什么意思 embroidery backing i'm back是什么时态?如果是我已经回来了,是不是用i've back我正在回来是i'm backingi'm back呢? back a loser中文(原句;with the best will in the world ,you may be backing a loser) We are going to come back back at six o'clock.否定句和一般疑问句 WE WILL BE BACK