1. Under means in a lower position than something else.

Pattern 1: verb + under + noun
We sat under the tree and had a picnic.

Pattern 2: verb + noun + under + noun
Let's put the desk under the window; then wel'll have a great view.

2. Under means covered by something else; underneath.

Pattern 1: verb + under + noun
The children hid under the table, thinking we couldn't see them.

Typical verbs before under:
be, hide, lie, rest, sit, sleep, stand, wait, walk

Pattern 2: verb + noun + under + noun
She stores all her boxes under the bed.

Typical verbs:
bury, find, hide, place, push, put, store, wear

3. Under means less than.

Pattern: under + noun
I'm sure she was driving under the speed limit.
He has three children under age ten.

Nouns commonly used after under:
any number, age, average, height, limit, maximum, minimum, norm weight

Expression:
to be under age—to not be old enough to do something
She can't vote because she is under age.

4. Under can indicate control.

Pattern 1: under + noun
Under this boss we have little freedom to express our own ideas.
You have a lot more benefits under the new insurance policy.

Typical nouns used after under:
boss, coach, contract, dictator, doctor, general, king, mayor, policy, principal, president, professor, supervisor, teacher

Pattern 2: under + the + noun + of + noun
She is under the care of a doctor.

Typical nouns after under the:
administration, care, control, dictatorship, direction, eye, management, presidency

Pattern 3: under + 0 + noun
The children are under supervision at all times.
They were arrested under orders of the chief.

Precautions while using Cathode Ray Oscilloscope

Warning

Never advance the Intensity Control so far that an excessively bright spot appears. Bright spots imply burning of the screen. A sharp focused spot of high intensity great brightness should never be allowed to remain fixed in one position on the screen for any length of time as damage to the screen may occur.