图像通信是通过（）传送、存贮、检索或广播图像与文字等视觉信息的业务。
参考答案：电信网络
— I wonder if I _____ smoke here.
— No, you ______ . Couldn't you see the sign "NO SMOKING" on the wall?[ ]
A. can; needn't
B. may; mustn't
C. must; can't
D. shall; won't
科研选题的步骤？
