prep.
1.在...地点 They were already waiting at the gate when I got there.当我到达那里时,他们已等候在门口了.
2.在...时刻 Jane will meet her boy friend at Christmas.简将在圣诞节和她男友见面.
3.向,朝,对着 Don't shout at me.别对我叫喊.
4.在...方面 He is an expert at troubleshooting.他是位排解争端的能手.
5.因为,由于 I woke at the sound of the bell.随着铃响,我醒了.
6.从事于,忙于 He is working hard at this thesis.他正在努力地撰写论文.
7.以(某种价格、速度等) They sold the cloth at a dollar a yard.他们以每码一元的价格出售这种布.