"I've got to get going." and "I have to get going." What is the difference between the two phrases? "I've got to..." Is "I've" always contracted? Is "I have got to..." correct? Thanks.

Are "lobby" and "lounge" interchangeable? Thanks for your help.

I hear people say that operation could be more on the surface while surgery means operation inside the body. I thought the two words are interchangeable.

In advertisements for photocopiers, the word "duplex" often appears. What does it mean? Thanks.

Do the words "operation" and "surgery" differ? Thanks.

Thanks. When someone asks me a friend's name and I don't remember. What should I say? "I forget his name"? or "I forgot his name"? I can not recall his name. It's a state that will go on unless someone tells me his name. Thanks.

When i realised that I had forgot to bring my dictionary, do I say "I forgot to ..." Or "I forget...." Is "I forget ..." a correct sentence? If so, when is it used? thanks.

Can we say there is some damage on /in the ceiling? Is this the correct sentence and which preposition should be used? Thank you.

If a cup has a crack, does it have a crack in /on it? Does it have a crack in/on the side? I think it should be in it, in the side. But I saw in a book, it was on the side. Someone is punched in/on the eye? When should be in used? When should

Thank you. I have the same confusion. I wonder when present tenses are used.