问题
填空题
用正负数的方式表示．
18℃______零下12℃______35℃______0℃______零下24℃______ 零下0.5℃______．
答案
18℃+18℃零下12℃-12℃35℃+35℃0℃0℃零下24℃-24℃零下0.5℃-0.5℃．
故答案为：+18℃，-12℃，+35℃，0℃，-24℃，-0.5℃．
搜题请搜索小程序“爱下问搜题”
用正负数的方式表示．
18℃______零下12℃______35℃______0℃______零下24℃______ 零下0.5℃______．
18℃+18℃零下12℃-12℃35℃+35℃0℃0℃零下24℃-24℃零下0.5℃-0.5℃．
故答案为：+18℃，-12℃，+35℃，0℃，-24℃，-0.5℃．
I can’t remember when I started collecting litter. But it was when I got tired of (1)_____litter nearby and realized that(2)_____ was going to pick it up. I live near a (3)_____ in Enshi, Hubei Province. I can walk there in three (4)_____! I (5)______ love going there to play with my dog. But one day there was so much litter there that I became very unhappy. I decided I had to clean up the forest. I wanted to (6)______ happy going there again. I made my (7)_____ trip to clean the forest that afternoon. I took a big black rubbish bag with me. Ten minutes (8)_____ starting to pick up litter, my bag was full! It had cans, bottles, broken glass and newspapers in it. From then on, I went to the forest four times a year to pick up the litter. I often (9) ______ there for three hours. It makes me feel 10)_____ to do something for the environment. After each trip , I(11) _____all the litter that I’ve found. If (12)______ of it is recyclable(可回收的), I keep it. I can’t (13)_____ why people drop litter. But I will keep picking it (14)_____ they stop dropping it. I know I am only doing a small bit to help(15) ______, but I still think it is important.
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莽草酸（C7H10O5）是制取抗“HlNl流感”的药物“达菲“的原料．试计算：
（1）莽草酸的相对分子质量______；
（2）莽草酸分子中C、H、O原子个数比为______；
（3）______g莽草酸含碳元素的质量为168g；
（4）对1岁以上的儿童推荐按照下列“体重一剂量表“服用“达菲“：
| 体重 | 小于等于l 5kg | 15～23kg | 23～40kg | 大于40kg |
| 每次用量 | 30mg | 45mg | 60mg | 75mg |