【单选题】What dose “End” at the end of the letter mean?
A.
Something attached to the letter.
B.
A complaint to the toy company.
D.
An encouraging response.
【判断题】If the letter contains documents other than the letter itself, the letter will include the word Enclosure.
【单选题】金属切削机床的主轴属于机器的( )部分。
【多选题】哪些项是研发项目最终必须交付的成果( )
【多选题】当污水处理采用生物脱氮除磷工艺时,其污泥浓缩与脱水采用下列哪几种方式更合适?( )
【单选题】关于6-磷酸果糖激酶-2的叙述错误的是: