There are a number of ways to guess in English. Here are some of the most common:
- I'd say he's about ready to quite his job.
- It might need some oil.
- He could be in the garden.
- It looks like a miniature motor.
- Perhaps he needs some time off work.
- Maybe they want to come and visit this summer.
- It's difficult to say, but I'd guess that it's used for cleaning house.
- I'm not really sure, but I think they enjoy hiking in the mountains.