凑路费

club together for travelling expenses

凑成整数

round up to a whole number

凑成一整套

collect a complete set

几种情况凑在一起

several things are happening at once

大家都凑到一起

everyone has gathered together

凑机会

take advantage of an opportunity

往前凑

move close to the front

凑上去问

go up to ask

把耳朵凑在门上听

put an ear to the door to listen

凑到耳朵边说

speak in someone's ear

他凑在一盏煤油灯边上写信。

He wrote a letter next to the oil lamp.