Chọn từ thích hợp Bill : Hey Alex. Alex : Hey Bill. Bill : Are you busy (1) before / later? Alex : Yes, sorry. I have to do my homework (2) after / in school? Bill : What about (3) Saturday morning / yesterday morning? Are you busy (4) then / next? Alex : Let me see. No, I’m not doing anything (5) on / in the morning. Why? Bill : Do you want to go mountain biking (6) on / in Saturday morning? Alex : That sounds awesome. Bill : Great! Where do you want to meet? Alex : Let’s meet in / under the park across (8) from / in the school. Bill : OK, great. See you (9) at /on Saturday. Alex : See you (10) before / later.