英语求助

take off (脱下）= put offby bike (通过骑自行车这种方式）in /on on (某一天的上午，下午，具体某一天,星期，某天 都用介词on)There are [some] trees on the hill.就括号里的提问问句是：How mane trees are there on the hill ?

1.off2.by3.on4.on

1.take off2.by3.in(此处只能用in,不能用on.但如果是其他的除car之外的交通工具,则用on,如bus,plane)4.onHow many trees are there on the hill?