单项选择题
Have you ever seen a ______ bag on the tableA．plastic s...
单项选择题Have you ever seen a ______ bag on the table
I'm afraid you've been ______. This bank note is a forg...
单项选择题I'm afraid you've been ______. This bank note is a forgery (伪造物).
It is required that such insulator (绝热体) ______ a heat ...
单项选择题It is required that such insulator (绝热体) ______ a heat resistant material.
