蚀变围岩
参考答案：
因热液交代作用而引起的围岩变化称为热液蚀变，而蚀变后的岩石称为蚀变围岩。
按WHO提出的克罗恩病的诊断标准，下列哪项不能确诊①节段性病变、②纵行溃疡、③全壁性炎症病变、④非干酪性肉芽肿、⑤裂沟或瘘管、⑥肛门部病变
A．①+②+③+④B．①+②+③+⑥C．②+③+④D．④+⑤+⑥
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.
（18）是（）
A. technology
B. video images
C. logical
D. physical
