Do you remember the license number of the bus? 5) 关于通讯工具 接在by之后的通讯工具名词,都是作为不可数名词,其前面不加冠词。但是这些名词在其他场合要加冠词。请比较: by radio by telephone by post by mail by satellite 和 a talk on the radio send the letter through the mail They sent a...