目前沪深证券交易所证券回购交易仅为国债。( )
参考答案：错
解析： 目前沪深证券交易所办理证券回购交易的券种主要为国债和企业债。
We _____ to wear warm clothes because it's hot inside.[ ]
A. needn't
B. need
C. don't need
D. haven't to
需求方规模经济
