如果将成语“朝秦暮楚”用在商业上，你认为该成语不能从侧面反映出中国古代(　　)

设函数f（x）=sin（2x﹣$\frac{\mathrm{\pi }}{2}$）（x∈R），则f（x）是（　　）

12枝铅笔，每4枝一份，分成了____份

    Today is Monday. The weather is fine, it is sunny all day. I had a busy day. In the morning, I went to school to learn Chinese. After school, I played basketball with my classmates and it made me feel happy because it was great fun! In the afternoon, I went for a walk with my good friend Lily. We went shopping on the way, We bought a lot of food, it was delicious. And I like hot food. I also bought some hot food. I loved the food very much. In the evening, I played tennis with my little brother. He was lovely, I didn't do my homework that day. We had dinner at home, My mother cooked for me. I had a good weekend today. Oh, my name is Bob.