营业员介绍商品时的语言要（）。
A、模糊、流畅
B、准确、流畅
C、小心、谨慎
D、小心、模糊
参考答案：B
The cinema has ______ screen,and it's ______ in the city. [ ]
A. a big; biggest
B. a big; the biggest
C. big; biggest
D. big; bigger
如何判断循环流化床锅炉的扰动属于内扰还是外扰？
