图样中,机件的对称中心线和轴线用( )画出。
A. 细实线
B. 虚线
C. 点划线
D. 双点划线
—_____ this your bag?
A. Yes,________
B. Is; it’s
C. Is; it is
Do; it do
The () layer of the OSI model organizes bits from the physical layer into logical data units called frames.
A. physical
B. data-link
C. network
D. transport
() is a protocol used for transferring files.
A. FTP
B. SMTP
C. TELNET
D. HTTP