Choose the correct options to complete the sentences

1. He is [an only|the only|only] child in the family. His mum and dad adore him.
2. I was completely at [the loss for|loss for|a loss for] words.
3. Maria fell in love with him [at the first sight|at first sight|at a first sight].
4. I don't understand you. Get to [a point|an point|the point] , please.
5. Please, give me [a ride|an ride|the ride] to the post office.
6. On [a second|second|the second] thoughts, I like your idea.
7. His mistake was just a slip of [a tongue|the tongue|tongue].
8. I heard about you on [a radio|the radio|radio] two days ago.