Explanation

The question of unemployment bristles with difficulties.

" with" preposition means accompanied by (another person or thing).

we use with a preposition because " unemployment " is accompanied by " with difficulties"

Explanation

We use in for long periods or refer future.

In is a preposition here.

We will go to Jupiter in the future ہم مستقبل میں مشتری پر جائیں گے

Explanation

We can also use by before a specific time.

By is a preposition here.

Here by 9 means نو بجے تک

Explanation

The word Grateful is generally followed by preposition To.

Grateful to someone means کسی کا احسان مند ہونا

I am extremely grateful to all the teachers for their help.

Explanation

Over is a preposition.

Over also means in many parts of the world.

All over the world means دنیا بھر میں

Explanation

We use beneath most commonly to describe the position of things which are at a lower level than something else.

The metro station is right beneath the airport.

The ground beneath is covered with flowers.

Explanation

ü  To ensure something is to make sure it happens -- to guarantee it.

ü  To insure something or someone is to cover it with an insurance policy.

ü  To assure someone is to remove someone’s doubts.

Explanation

We sat by the air

ہم ہوا کے کنارے بیٹھ گئے۔

Explanation

I took a rope for a snake. میں نے رسی کو غلطی سے سانپ سمجھ لیا۔

Take for means غلطی سے سمجھ لینا

Explanation

The correct phrase is "knocked at the door."

The preposition "at" indicates a location or position in such expressions.