落后

Modesty helps one to go forward, whereas conceit makes one lag behind.

The programme has fallen so far behind that there is little chance of meeting the deadline.

After all he's a man of forty, so he gradually fell behind others after four laps.

trail behind by one point at half time

lag behind in one's work

trail behind the age/times

be ten years behind; be a decade behind

The government should take immediate and practical measures to change the backwardness of the underdeveloped mountain areas.

backward production tools

backward areas; less developed areas

outdated capacity

backward thoughts/thinking; one's thoughts are far behind the times

be backward in techniques