《焊工考核细则》中规定螺柱焊平焊试件的位置代号为（）。
A.1S
B.2S
C.3S
D.4S
参考答案：A
He wrote a letter to me _______ that his trip to Japan had been put off because of the bad weather.
A．inform
B．informing
C．informed
D．being informed
简述原油含水过多在炼制中的危害？
