题目

为提纯下列物质（括号内为杂质），所用的除杂试剂和分离方法都正确的是（ ） 序号不纯物除杂试剂分离方法 ACH4（C2H4）酸性KMnO4溶液洗气 BC2H5OH（乙酸）新制生石灰蒸馏 C乙酸乙酯（乙醇）饱和Na2CO3溶液蒸馏 DNH4Cl溶液（FeCl3）NaOH溶液过滤 A . A B . B C . C D . D 答案：BEvery day in China, about 200 million children go to school. Many of them take school buses. What should we do to keep these students safe on the road? On April 5, the State Council (国务院) published new rules about school bus safety. These new rules are much stricter than the old ones. Under the new rules, local governments must make sure that students attend nearby schools or boarding (寄宿的) schools to reduce traffic risks. Also, local governments must help kids in the countryside reach their school buses. From now on, school buses have a speed limit of 80km per hour on highways and 60km per hour on normal roads. While on the road, other cars must let school buses go first. The new rules also say that school buses must never be overloaded (超载的). They have a speed limit of 80 km per hour on highways and 60 km per hour on normal roads. There are many other rules as well. A school bus must have more than seven seats. On each bus, there must be at least one adult to keep an eye on the kids. Each school bus must have a fire extinguisher (灭火器), a first aid box and a GPS. Last year, a series of school bus accidents happened in China. To stop such accidents, the Central Government decided to strengthen the rules for school buses. The most serious accident happened in November in Gansu, when a nine-seat minibus crashed. There were 62 children inside, and 21 of them died. 1.Under the new rules, which of the following is NOT true? A．School buses must not be overloaded. B．School buses must drive 80 km/h or less on normal roads. C．School buses can go first when there are other cars. D．School buses must drive 80 km/h or less on highways. 2.The phrase “keep an eye on” in Paragraph 6 has a similar meaning to “__________”. A．look after B．play with C．look for D．chat with 3.According to the new rule, a school bus must have the following EXCEPT __________. A．a GPS B．more than seven seats C．a parent of one of the students D．a fire extinguisher and a first aid kit 4.The government made new rules for school buses because __________. A．21 students died in school bus accidents last year B．the government encourages all students to take school buses C．200 million children in China go to school by bus every day D．school buses in China were not safe enough before