题目

下列实验能达到目的的是   A 用溴水鉴别苯和正己烷          B  用BaCl2溶液鉴别SO42-和 SO32-   C 用浓HNO3与Cu 反应制备NO2     D 将混有HCl的Cl2通入饱和NaHCO3溶液中除去HCl 答案：C29、 Lots of people like diving into water, because they can explore the underwater world. But there is another kind of diving. Some people dive into the sky! This is really a very exciting sport. A skydiver goes high up in the air on a plane. Then he jumps off the plane and floats（飘） in the air with the help of a parachute（降落伞）. A parachute is like a huge umbrella. It is put on the back of the skydiver. When the skydiver reaches a certain height, he will pull a string（细绳） and the parachute will open up in seconds and carry him gently（轻轻地） down to the ground.  Skydivers like doing a lot of fascinate tricks in the air. After jumping off the plane one after another, they will try to stay in the air and hold each other’s hands. They can form different shapes. Is it safe to do skydiving? Yes, as long as we receive right training. But sometimes, accidents do happen. In Canada, two skydivers were killed in 1991 when they jumped off the plane. Because their parachutes got tied up with each other, the parachutes couldn’t open up and both crashed down and died. 1．Why do people like diving into water? 2．How does a skydiver go up into the sky? 3．What does a parachute look like? 4．Where does a skydiver put his parachute? 5．Why were two skydivers killed in Canada?