题目

下列关于基因、环境、蛋白质与性状关系的描述，正确的是（ ）A.基因与性状呈线性关系，即一种性状由一个基因控制B.生物体的性状主要是由基因决定的C.基因都是通过控制蛋白质的结构来直接控制性状的D.只要基因型相同，表现型也一定相同 答案：【答案】B【解析】1、基因与性状不是简单的线性关系，一对相对性状可以由多对等位基因控制，一对等位基因也可能与多对相对性状有关。2、基因可以通过控制酶的合成进控制细胞代谢而控制生物的性状，也可能通过控制蛋白质的结构直接控制生物的性状。3、在自然界中，不仅存在单基因对性状的控That cold January night, I was growing sick of my life in San Francisco. There I was, walking home at one in the morning after a tiring practice at the theater. With opening night only a week away, I was still learning my lines. I was having trouble dealing with my part-time job at the bank and my acting at night at the same time. As I walked, I thought seriously about giving up both acting and San Francisco. City life had become too much for me As I walked down empty streets under tall buildings, I felt very small and cold. I began running, both to keep warm and to keep away any possible robbers（抢劫犯）. Very few people were still out except a few sad-looking homeless people under blankets. About a block(街区) from my apartment, I heard a sound behind me. I turned quickly, half expecting to see someone with a knife or a gun. The street was empty. All I saw was a shining streetlight. Still, the noise had made me nervous, so I started to run faster. Not until I reached my apartment building and unlocked the door did I realize what the noise had been. It had been my wallet falling to the sidewalk.Suddenly I wasn’t cold or tired anymore. I ran out of the door and back to where I’d heard the noise. Although I searched the sidewalk anxiously for fifteen minutes, my wallet was nowhere to be found. Just as I was about to give up the search, I heard the truck pull up to the sidewalk next to me. When a voice called from the inside, “Alisa Camacho?” I thought I was dreaming. How could this man know my name? The door opened, and out jumped a small red-haired man with an amused look in his eyes. “Is this what you’re looking for?” he asked, holding up a small square shape. It was nearly 3 a. m. by the time I got into bed. I wouldn’t get much sleep that night, but I had got my wallet back. I also had got back some enjoyment of city life. I realized that the city couldn’t be a bad place as long as people were willing to help each other.1.How did the writer feel when she was walking home after work?A.Cold and sickB. Lucky and hopefulC. Satisfied and cheerfulD. Disappointed and helpless2.From the first paragraph, we learn that the writer was busy_____.A. solving her problem at the bankB. taking part in various city activitiesC. learning acting in an evening schoolD. preparing for the first night show3.On her way home the writer_____A. lost her wallet unknowinglyB. was stopped by a garbage truck driverC. was robbed of her wallet by a man with a knifeD. found some homeless people following her4.In the fourth paragraph, why did the writer say she was dreaming?A. Someone offered to take her back homeB. A. red-haired man came to see her. C. She heard someone call her nameD. Her wallet was found in a truck5.From the text, we can infer that the writer_____A. would stop working at nightB. would stay on in San FranciscoC. would make friends with cleaners.D. would give up her job at the bank