use of under

#Under is a preposition. When we use under as a preposition, it is similar to below. We use under to talk about something that is below or lower than something else: The cat is under the table. His shoes were under his bed. #When we use under, we can also mean that one thing is touching or covering something else. We do not use below in this way: ✅The wreck of the Titanic still remains under the sea. ❎Not: … below the sea. ✅He had hidden the money under the floorboards. ❎Not: … below the floorboards. ##Warning: We don’t use under to refer to something in a lower position than something else. We use below: ✅Venus is just below the moon right now. ❎Not: Venus is just under the moon … #Age We use under, not below, to refer to age: You have to be under 18 to get an allowance. They have three children under the age of five. #Measurements We use under, not below, to talk about measurements of time and weight: We finished the project in under a year and a half. The bag was just under 10 kilos, so I was able to bring it on the plane. #When we talk about height and temperature, we use below not under: ✅The roof of the new building is just below the height of the church and I think it distracts from the church. ❎Not: … under the height of the church … The liquid must be kept below five degrees. (preferred to … under five degrees.)