观察法可以利用录像、照相、录音等手段,还可以通过观察()来构想人们的行为.
参考答案:痕迹
步行1.6km/h对应的METs值为()
A.1.5~2.0
B.2.0~2.5
C.3.0
D.3.4
E.5.6
F.6.7
Asynchronous Transfer Mode (ATM) is a (16) that promises to change the fabric of local and wide area communications. The key advantage of ATM is the capability to move voice, data, graphics and (17) at speeds of up to 2 gigabits per second. An ATM switch allows you to create a (18) network that is completely independent from the (19) configuration of the network. ATM uses a (20) called cell switching to convert data into fixed length cells of 53 bytes each, so they can be switched very quickly and efficiently.
A.technology
B.video images
C.logical
D.physical