Attend vs. Attend to

Although it's the same verb with the only difference that one of them is followed by 'to', they have completely different meanings.

'To attend' means to go to an event, place, etc. while 'to attend to' means to deal with something or help someone. On the first one, you don't need any preposition after, but on the second one, you need 'to'. Here you have some usage examples:

They couldn't attend the meeting because they were sick.

I have to attend to him because he can't do it on his own.

To make it more clear I give you this sentence:

I couldn't attend the funeral because I had to attend to many things at work.

I hope it's clear! If you have any questions, just ask me on the comments below.

Gemma