中国之所以能在国际舞台上发挥越来越重要的作用，是因为（  ）
①中国的综合国力增强了   ②中国的国际地位提高了
③中国人充满了自信         ④中国人以负责任的态度，坚持正义地处理国际事务

下列关于我国人口的说法，不正确的是（　　）

阅读短文，判断对（T）错(F)

     I'm Lingling. I have got a new bike. It's a nice bike. I go to school by bike every day. My mother is a teacher. Her school is near our home. So she walks to work. My father is a doctor. He goes to work by car.

函数$y={\sin }^3\left(3x+\frac{\mathrm{\pi }}{4}\right)$的导数是（　　）