A:ab=cd
B:ac=bd
C:ac=db
D:ad=bc
近年来某特大城市的化学工业,不断由中心城区外迁,分析导致这一现象的原因。
Hello, I'm Jack. I am a student. I have many friends at school. I go to school by bus; the school is near my home. Tom goes to school by bike. John goes to school by car. His mother drives(驾驶) the car. Mary goes to school by taxi. We are happy at school.
①李晓和好友积极参与社会公益活动,服务社会 ②大家应共同营造“人人为我,我为人人”的氛围
③从事志愿者活动意味着承担更多的责任,得不到回报 ④李晓和好友开展“献爱心”活动,努力做负责任的公民
火星的质量和半径分别约为地球的 110 和 12 ,地球表面的重力加速度为g,则火星表面的重力加速度约为( )
“六合之内,皇帝之土;乃今皇帝,一家天下。”这则纪功刻石说的是( )