Whether (=whether or not) is logically impossible here because the verb to believe (unlike e. g. the verb 'to know', possible in its place) doesn't allow for mutually exclusive options (can or cannot here) and usually deals with something definite. So 'that' is the correct choice for this sentence.
First I would change the "bought a ticket" to "have a ticket" or "a ticket is needed". After all, you probably don't care who bought it, but only who has one when they get there :)
A friendly reminder would be "A ticket is needed for admission" (no ticket, you don't get in)
A more stern reminder would be "A ticket is required to get in" (like a teacher ...
You have this correct:
We could watch an interesting series or anime.
This is the usual way to refer to a choice from the group of interesting things which are series or animes.
But it will be ambiguous if plural (so the article is absent) and will be understood on the sense of the particular adjectives and nouns:
Look at the big buses and taxis
The short answer is that it's ambiguous.
Interesting could be interpreted to modify both series and anime, or just series.
To be certain, you need to repeat interesting or rewrite the sentence.
We could watch a series or anime; both are interesting.
She is both a singer and actress.
She is both a singer and an actress.
She is a singer and actress. [buzzer]
She is a singer and an actress. [good style]
If things are not defined, leave them that way.
He is a mechanic and an engineer.
The meaning might not change, but it sure sounds bad not to keep two articles.
The Chicago Manual of ...
Your first example is typical informal spoken English. Though it is colloquial, I should hesitate to use it in a written or formal context; others might disagree.
As you surmise, the second example means exactly the same thing - that he acts in a manner indicating that.... - but is more formally stated. An alternative to He acts as if... is He acts as ...
First of all, I don't think this is a matter of "so" at all. It is essentially the issue of commas with coordinating conjunctions: FANBOYS.
Yes, when two independent clauses are connected with a conjunction, a comma is often used. This is not a strict rule, but a general guideline (note how I used a comma before 'but' even though it is not needed/...
The idea [that war is obsolescent] may seem preposterously utopian.
That war is obsolescent is a declarative content clause. It says what the contents of that idea are, as it were. Content clauses are also called noun clauses.
The sad truth [that there aren’t many honest people in the world] seems to be true.
The bracketed clause is a content clause: it ...
The sentences are quite similar, but there is a subtle shift in emphasis.
At the core of both statements is a logical statement: unless he works, he will starve. In the latter construction (without "either"), the statement is clear, direct, even blunt.
Using "either" takes the emphasis off the logical statement, and instead shines a spotlight on the ...
There is not much difference. When discussing two alternative possibilities or outcomes, one of which must occur, 'either' can be omitted. If it is included, it adds emphasis.
We can use either...or to emphasise a choice. (Either…or is used to
refer to two things or people.) In most cases 'either' can be omitted.