Question: When I asked my friend for advice, she said, “You could look on the internet”. Is this the same as “You should look on the internet”?

In these two sentences, could is being used to present an option. The speaker doesn’t necessarily advise this option. If the speaker uses should, it means the speaker thinks this may be the best idea.

Compare: You could talk to your parents or friends about it, but I really think you should speak with your teacher directly about your grades.

Can / could has many meanings:

? Ability (I can play the piano.)

? Permission (I can come to your party – My parents say it’s ok.)

? Availability (I can come to your party – I don’t work that day).

The sentence above uses could to indicate availability. There are three available options.