彼らはおそらく来週到着するでしょう。
tbd
They're very likely to arrive next week.
We think it possible that they may arrive next week.
I think it's very likely that they'll arrive next week.
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おそらく， 恐らく
1. probably, (most) likely, in all likelihood, I suspect, I dare say, I'm afraid
大概、很可能、几乎肯定地说、我推测、我敢说、恐怕
する， 為る
1. to do, to carry out, to perform
2. to cause to become, to make (into), to turn (into)
3. to serve as, to act as, to work as
4. to wear (clothes, a facial expression, etc.)
5. to judge as being, to view as being, to think of as, to treat as, to use...
做，作，干，执行