①将三块小石头放在盛有少许清水的容器内形成三个小岛,小岛间用两根等长的小木条连接起来,这样蚂蚁只能通过由小木条搭成的“桥”从一个小岛到达其它的小岛.
②先将饥饿的蚂蚁放在B岛上,食物放在C岛上,A岛什么都不放,发现蚂蚁经过几次寻找后,在C岛上找到食物.
③小组成员将连接BC岛的“桥”和AB岛的对换,结果发现蚂蚁并没有爬向有食物的C岛,而直接爬向A岛.
①温暖湿润 ②寒冷干燥 ③海拔较低 ④雪山连绵
Cassie is a girl in Yuying Middle School. Her room is not tidy. It is in a mess. Her mom asks her to clean(打扫) the room and Cassie asks Carl for help.
"Carl, can you come to my room now and help me clean it?" asks Cassie.
Carl is Cassie's brother. Carl's room is always tidy. His schoolbag is on the desk, the chair is under the desk and the radio is in the bookcase. He doesn't ask his mom "Where is my dictionary?" or "Where is my schoolbag?" He can always find his things in the room.
车型 |
甲 |
乙 |
丙 |
汽车运载量(吨/辆) |
| | |
汽车运费(元/辆) | | | |
—Sam did.