如图环状DNA（质粒A）上含抗氨苄青霉素和四环素抗性基因．现将人的生长激素基因由a点切开嫁接到质粒A上形成重组质粒，将重组质粒导入细菌B并获取“工程菌”进行培养．结果人的生长激素基因及抗氨苄青霉素基因都能成功表达，而四环素抗性基因不能表达．这一事实说明（   ）

    Humans like to live and work in groups. Language is the “cement(胶合剂)”____holds these groups together. Language is part of culture. Culture, in this sense,____ (mean) all those customs, skills, and attitudes that are part of the behavior of a ____ (particularly) group. What you think ____ what you want in life are all affected by the culture of the group in which you ____( raise). Groups of people live in different ways. They may have different skills, organizations, and art forms. Their family life may be completely different from yours.

    Human beings are inventive animals. They can decide to change their cultures in order to meet various ____(situation). Of all living things, human beings are the ____(clever). They can choose ____(live) in many environments and in a wide variety of ways. Only human beings can choose where and how they want to live and then improve the physical environment to help ____(they)realize these choices.

    Acquiring the wisdom to make wise choices ____ (be)the lasting challenge of being human.

分一分

38个气球，每6个扎成一束，可以扎成____束，还剩____个。

柔美—____  欢快—____  柔软—____  晶莹—____

如图，一列简谐横波沿x轴正方向传播，波幅A=2cm，周期T=1.2×10^﹣2s．t=0时，相距50cm的两质点a、b的位移都是 $\sqrt{3}$ cm，但振动方向相反，其中a沿y轴负方向运动．下列说法正确的是（   ）