柴油发动机混合气在（）形成。
A.缸内
B.气门背面
C.进气管
D.化油器
参考答案：A
Our country ______ great changes in the last 30 years and it is no longer it used to be.
A．went through; what
B．went through; that
C．has experienced; that
D．has experienced; what
真核生物核心启动子TATA盒位于转录起始区的（）。
A.-10bp区
B.+35bp区
C.+10bp区
D.-30bp区
E.+1bp区
