1. I am looking for a dress to wear to the meeting.

2. I am looking for a shirt to wear to the birthday party.

3. I am looking for suits to wear to the conference.

(Are they all grammatical? Why do we have to use the preposition 'to' before a place? Can we use 'at' or 'in' instead of 'to'? What is the difference between them in meaning?)

They are all correct.

The prepositions "at" and "to" in these sentences mean about the same. You could use either one. However, "to" is probably used more often than "at" in these sentences.

One could say you are wearing the shirt to the meeting and then take it off at the meeting. If you say you are wearing the shirt at the meeting there is no room for misunderstanding.

Don't ever end a sentence with "at" please! Like: where did you get the shoes at? Yuk!!!

1. Yes, the sentence "I am looking for a dress to wear to the meeting" is grammatically correct. It indicates that you are searching for a dress specifically to wear to the meeting.

2. Similarly, the sentence "I am looking for a shirt to wear to the birthday party" is also grammatically correct. Here, you are expressing your intention to find a shirt specifically for wearing to the birthday party.

3. The sentence "I am looking for suits to wear to the conference" is also grammatically correct. It suggests that you need multiple suits for wearing to the conference.

Now, regarding the use of the preposition 'to' before a place, it indicates the destination or purpose of your clothing. In these sentences, the preposition 'to' is used to convey that you are looking for clothes specifically intended for wearing on these occasions. You are searching for a dress or a shirt or multiple suits that are suitable for those particular events.

In some cases, it is possible to use alternative prepositions like 'at' or 'in' instead of 'to', but the meaning would slightly change:

- "I am looking for a dress to wear at the meeting" suggests that you are looking for a dress to wear while attending the meeting, without explicitly stating it is specifically for the meeting.

- "I am looking for a dress to wear in the meeting" implies that you will be wearing the dress inside the meeting itself, which might imply a higher level of formality.

In summary, using 'to' before a place in these sentences helps to clarify the purpose or destination of the clothing, indicating that you are looking for something specifically suitable for those events. However, alternative prepositions like 'at' or 'in' could be used to convey slightly different meanings.