1 to be connected

2 traffic

3 transportation

4 communications

5 liaison

1 cause

2 origin

3 root cause

4 reason

5 classifier: 个 gè

1 old variant of 因[yīn]

1 thus

2 consequently

3 as a result

1 because

2 owing to

3 on account of

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 mutually related karma (idiom); fates are intertwined

2 interdependent

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