问题 选择题 Read and choose. (选出与图片相符的句子) ( ) 1. A. He likes listening to music. B. He likes drawing pictures. C. He likes playing football. ( )2. A. My sister went skating. B. my sister had a cold last week. C. My sister ate the turkey yesterday. ( )3. A. She's from Canada. B. She's from America. C. She's from China. ( )4. A. Let's play computer games. B. Let's take a picture together. C. Let's have an English lesson. ( )5. A. I can play the erhu. B. Keep in touch. C. This is Peter speaking. 答案 1.A 2.A 3.B 4.A 5.C
B． 混合液中：c(HA)＋c(A－）＝a mol·L－1