根据短文理解，选择正确答案。

    We are all learning English, but how can we learn English well? A student can know a lot about English, but maybe(可能)he can't speak English.

    If you want to know how to swim, you must get into the river. And if you want to be a football player, you must play football. So, you see. You can learn English only by using it. You must listen to your teacher in class. You must read your lessons every day. You must speak English to your classmates and also you must write something sometimes. Then one day, you may find your English very good.

下面关于音调和响度的说法中正确的是                            （   ）

直接写出结果．

9－5＋3＝____

6＋0＋3＝____

如图，是将抛物线y=﹣x²平移后得到的抛物线，其对称轴为x=1，与x轴的一个交点为A（﹣1，0），另一个交点为B，与y轴的交点为C．

依次填入下列横线处的词语，最恰当的一组是                      （   ）
①12月19日，中海油深圳分公司启动海管         应急预案，及时关停了番禺30—1和惠州21—1相关平台的生产，终端目前正在加速泄压。
②昨日上午9时45分，武汉二七长江大桥北主跨最后一块钢梁安装到位，标志着这座世界上最大跨度的三塔斜拉桥、最大跨度的结合梁桥顺利实现全桥         。
③如果说接送学生的车对交通           的影响是显性的，那么，家长乱停车与学生德育挂钩，法律和社会的伤害则是隐性和长期的。