Yes, it is grammatically correct to say "The haunted house looks very mysterious to you." You can also say "You find the haunted house very mysterious."
The correct phrasing would be "they look very similar" or "they look alike."
No, it is correct to say "all the children played very nicely together" as "nicely" is the adverb form to describe how they played.
Yes, it is correct to say "for forever." This phrase is often used informally to emphasize the idea of something lasting indefinitely or forever.
No, "ofttenly" is not a standard English word. The correct word is "often."
Yes, that is correct usage.
No. For example, it is perfectly correct to say, "It was very hot today."
Yes, this is correct.
There is no such word as "oftenest" - the correct usage of comparison with the word "often" is to say "more often" and "most often."Other options using the word "often" are "as often as" or "quite often."
This question is not clear on exactly what you are asking. What type of sentence are you using the word "what" in? If you are simply asking can one say "What?", then yes, that would be correct but not very mannerly. It is more polite to say "Pardon?" or "Excuse Me?".
"Three and six hundredths" is the correct form. In technical contexts it is often said "three point oh six", which is considered correct in those contexts.
Very often our behavior, what we say and do, is influenced by our "values."
yes, you can say it that way :)
It would be correct to say that they send messages to each other often. You could also say, they send messages to other people, often. It makes no sense to say they send messages to other.
It could be O O five or zero zero five, which is more correct, though people often say O when it is actually a zero.
gloat, but I can't say it is used very often as a noun.
It depends on the context.In informal talk you can often simply say "on", though it will not be grammatically correct in all situations.For example they are, is he ovat in Finnish. But many would simply say he on.