1 what?

2 something

3 anything

1 why?

2 for what reason?

1 by means of

2 through

3 via

4 to pass through

5 to get through

6 to adopt

7 to pass (a bill or inspection etc)

8 to switch over

1 to be connected

2 traffic

3 transportation

4 communications

5 liaison

1 to go smoothly

2 prosperous

3 going well

1 lit. doesn't (even) enter a single aperture (of one's head)

2 I don't understand a word (idiom)

3 it's all Greek to me

1 grasp this fundamental point and all the rest will follow (idiom)

1 to act in collusion (idiom)

1 mutual exchange of assistance (idiom)

2 to benefit from each other's strengths and make up each other's shortfalls

3 to reciprocate with material assistance

4 scratch each other's back

1 What brings you here? (idiom)