题目

利用细菌大量生产人类干扰素，下列叙述正确的是   A．用适当的酶对运载体与人类干扰素基因进行切割与粘合   B．选用细菌作为重组质粒的受体细胞是因为细菌繁殖快   C．通常通过检测目的基因产物来检测重组DNA是否已导入受体细菌   D．重组DNA必须能在受体细菌内进行复制与转录，并合成人类干扰素Everybody is nervous on the first day of school.Here are a few steps to help you look better and feel more comfortable.Plan ahead.It's the most important.Plan out what you're going to wear.Make sure that you have all your school things，such as paper，pens and pencils.You can also visit the school and take a look around.Get your schedule(时间表) before the first day of school and look it over a few times.There's nothing worse than looking terrible on the first day of school.Set an alarm clock to wake you up on time.Have a good breakfast.You would be surprised at how much happier and more focused(专心的) you will be after having a good breakfast.Try bread，fruit or other healthy food.Remember to avoid sugar－rich food，since it may make you less focused.Smile and be friendly.Everyone would like to be friends with those who are kind and friendly.Smiling can help you get on well with others.Also，you can improve a lot in your studies when there is a friendly atmosphere(气氛)，because others will be happy to help you.Have fun.School isn't always boring.Do something crazy，but remember not to be disruptive(破坏的) when you should pay attention.If you want the time to fly by，enjoying yourself is a great way to make it happen.1.What is the most important on your first day of school according to the passage？(不超过5个词)________________________2.Why should you avoid sugar－rich food？(不超过10个词)________________________3.What's the passage mainly about？(不超过15个词)________________________