二氧化碳能灭火的原因是()。
A、它是气体
B、它在高压低温下能变成干冰
C、它溶于水
D、一般不能燃烧,比空气重,形成气体覆盖层隔绝空气
参考答案:D
短文填空 先通读下面的短文,然后根据短文内容和所给首字母,在空格内填入一个适当的词,使短文意思完整。所填单词必须在答题卡标有题号的横线上完整写出。(本大题共6分,每格0.5分)
Who was Leonardo da Vinci? You may answer without t 小题1: : “He is the painter of the Mona Lisa.” What e 小题2: do you know about him? Da Vinci was more than just a great artist in history. He’s also f 小题3: as a scientist and an inventor.
Leonardo da Vinci was b 小题4: to a rich family in Florence, Italy, in 1452. From childhood, Leonardo was given a good e 小题5: and he showed talent at painting. By the age of 26, da Vinci had already become a famous painter.
He designed many i 小题6: machines. Da Vinci’s idea l 小题7: to the modern tank(坦克). Though da Vinci never b 小题8: many of the inventions he designed, some of the things he i 小题9: in the late 1400s are in use today.
As a scientist, da Vinci was very interested in the h小题10: body. He spent a whole year c 小题11: up dead bodies in hospitals to learn about human anatomy(解剖学). He made more than 200 d 小题12: of bodies.
下列探究活动中不需要测平均值的是:
A.探究花生果实大小的变异
B.探究光对鼠妇生活的影响
C.测定种子的发芽率
D.为家长设计一份午餐食谱