What does 'go along with' mean?

English as a Second Language English Teacher Explanations (ESL Tests)
#1

Business Idiom in English, Intermediate level

ESL/EFL Test #128 [color=blue]“Ways of disapproving”, question 6

They can’t possibly go … with your suggestions because it will involve too much expenditure.

(a) over
(b) along
© in
(d) above

Business Idiom in English, Intermediate level

ESL/EFL Test #128 [color=blue]“Ways of disapproving”, answer 6

They can’t possibly go along with your suggestions because it will involve too much expenditure.

Correct answer: (b) along

Your answer was: [color=red]incorrect
They can’t possibly go in with your suggestions because it will involve too much expenditure.
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Hello Teachers

Why dont we use “go in with” here? What is the diference between Go in with and go along with?

#2

.
‘Go in with’ means ‘join’, which is not the intention here. ‘Go along with’ means ‘agree to, follow’.
.

#3

Good Evening!
Is this sentence correct:
She is going along with her best friend.

#4

As it stands, yes, but presumably they are going somewhere.