同步发电机并列时脉动电压周期为20s，则滑差角频率允许值ωsy为（）。
A、0.1%
B、0.2%
C、0.26%
D、0.52%
参考答案：A
— What do you think of earthquake, Zhang Hong?
— Terrible. people lost their hometown during the earthquake.
A．Five thousands
B．Thousand of
C．Three thousands of
D．Thousands of
按要求改写句子。
(1)黄昏时分，朝霞染红了半个天空。（修改病句）
(2)维吾尔姑娘更是漂亮得叫人不敢正视。（缩句）
(3)有些维吾尔老乡把洗过的衣服直接摊铺在沙漠上晾晒。（改成“被”字句）
