装置中管线吹扫,按物料介质不同,分别在逐条管道中进行吹扫,应()。
A、先吹总管,后吹支管
B、先吹支管,或吹总管
C、同时吹总管和支管
D、无先后限制,自由吹扫
参考答案:A
Jim and I _______ lunch. [ ]
A. having
B. have
C. is having
D. are having