opening soon! What is the part of speech of opening?

Where did this appear? Did you hear that? If you hear it, then it is most likely Open it soon, open and it are pronounced together.

If it is written, it may be subject + be + verb ing, which is the future tense of the present participle. Sometimes be can be omitted or the subject and be can be omitted at the same time. Most of them are omitted in promotional slogans.

Give examples respectively, such as:

1. The bar is opening soon, that bar will open soon.

2. The title of the flyer reads "New Club Opening Soon!" A new club is about to be established!

3. The notice board at the entrance of the store reads: "Opening soon".

In other words, the latter two are generally not spoken, but written in the nature of announcements.