感烟探测器按灵敏度可分为三级。一级灵敏度的探测器一般是（），二级灵敏度的探测器是（）

Although he is one of China’s most famous scientists, Yuan Longping r 小题1:  himself as a farmer, for he   小题2: the land to do his research. Indeed, his s小题3: face and arms and his slim, strong body are just like  小题4: of millions of Chinese farmers, for whom he has  小题5:(拼搏) for the past fifty years. Dr Yuan Longping grows 小题6: is called super hybrid rice. In 1974, he became the first agricultural   小题7: (先驱) in the world to grow rice that has a high o小题8:. This special strain of rice makes it  小题9: to produce one-third more of the crop in the same fields. Now more than 60% of the grain produced in China each year is  小题10: this hybrid strain.

脱硫方法可分为哪几类？干法脱硫的特点是什么？目前以天然气和轻油为原料的氨厂和甲醇厂常用的脱硫方法有哪些？

明代是四唐分期说的定型时期，代表论著是（）。

简述角材零件经淬火后，产生变形现象的一般规律和形式。

螺旋桨桨叶面上的B区是指（）的区域和A区两侧边缘、吸力面0.7R以内范围。

A.0.3～0.5R

B.0.4～0.7R

C.0.5～0.8R

D.0.6～0.9R