一定温度下，在1L的密闭容器中发生可逆反应：N2（g）+3H2（g）2NH3（g

Many a new measure ________put forward to reduce air pollution so far. [ ]

A. have been  

B. has been

C. was  

D. were

已知关于x的不等式|x-2|+|x-3|＜a

（Ⅰ）当a=2时，解不等式；

（Ⅱ）如果不等式的解集为空集，求实数a的取值范围．

句型转换。

1. Jim will watch the ballet tomorrow evening. (改为一般疑问句 )

                  Jim               the ballet tomorrow evening?

2. We clean our classroom every day. (用 tomorrow改写句子 )

   We                                            classroom tomorrow.

3. The good girl always looks after the old woman. (改为同义句）

   The good girl always                            the old woman.

4. They will do some shopping this Sunday. (对画线部分提问 )

                               they               this Sunday?

5.  there , three ,be , will , films , next , interesting , month (连词成句)

                                                   ___               

烧结时，燃料的最适宜粒度为（）。

A.0～3mm

B.0～5mm

C.0.5～3mm

标准中规定实际尺寸与称尺寸之间有一允许差值，叫做（）。