有形市场最主要的形式就是证券交易所。 ( )
参考答案:对
Jack Chan _____ to Hollywood a few years ago. Now he ______ a famous
movie star.[ ]
A. went; is
B. has been; is
C. is; is
D. was; was
井下空气中一氧化碳浓度较高时,会使人()。
A、中毒
B、窒息
C、呼吸困难