蛋白质变性在下述哪些方面得到应用 A．酒精消毒 B．高压蒸汽消毒 C．紫外线照射

根据短文内容和所给的中文提示，写出空白处各单词的正确形式，每空限填一词。

I am a middle school student and I'm  小题1:  (十五）years old, I’m quite healthy.     小题2:   (然而）, one year ago I was fat. I loved chips and chocolate, and I got tired   小题3: （容易地）. One morning, I saw some young men running in the park. They looked really fit and ___小题4:____(积极的) . So I started running from   小题5: （那时）on .

Now I have a 1.5-mile run every morning, I   小题6:  ( 喝 ) milk and eat fruit and vegetables____小题7:______(代替) of chips and chocolate. These good eating habits and running help to build me up. I have great fun running. I feel well and look fit. Running has    小题8:   (成为) my favorite sport, I'm    小题9: （确信）I will do well in the boys' 800-metre race in our school sports meet.

If you want to be healthy,    小题10: （加入）us !

4能整除24。[ ]

在缓慢增长的早餐食品市场上许多占有统治地位的公司转向别处谋求增长时，甲早餐食品公司并不甘心承认早餐食品行业可能已经成熟老化，而是通过促销创新，不断向现有产品范畴中输入新的活力，其收益相当可观。在2015年之前的5年中，甲公司早餐食品创下了几乎两位数字的年增长率记录，而同一时间内竞争对手的市场份额却下降了。甲早餐食品公司采用的发展战略属于（）。

A.市场渗透战略

B.市场开发战略

C.产品开发战略

D.差异化战略

氧气筒压力下降至多少时不宜再用

A．5kg／cm²

B．8kg／cm²

C．10kg／cm²

D．15kg／cm²

简述微生物在生态系统中的作用