I'm very late to this party, but after reading the existing answers, I'd like to add a little something for future readers.
Jake lived in N.Y. (until, before) he was thirty years old, and then he went to LA.
If you use "until", it means that the period during which he lived in N.Y. ended when he was thirty years old, not before. Therefore he definitely ...
Not in that sentence. Either
The apple was too heavy so it fell down.
The apple fell down because it was too heavy.
Because it was too heavy, the apple fell down.
(Though the last example places particular focus on the falling and is not so common)
There are sentences that could have both "so" and "because":
I was so happy ...
Your sentences are both problematic in several respects. Correcting bad grammar is not what we do on this site but here are some suggestions.
Whereas does not work in your example. Whereas balances or compares one thing against another. You will find numerous examples of its use online.
Jane does not have the qualifications for this job whereas Margaret ...
In abstract terms, this is a sentence which uses a form of the verb "to be" to link its subject to a subject complement. The basic structure is simple:
"X is Y."
The subject is "this", and the main verb is "is". Simple, right? ... However, the subject complement ("Y"), is a little bit complex and consists of the entire phrase, "the reflection of who you ...
But, of course,
and is just as grammatical and idiomatic.
I do remember hearing decades ago stylistic advice not to start an independent sentence with "And" or "But." Those were suggestions on style rather than rules of grammar, and opinions differ on style. Moreover, suggestions on style are best interpreted as meaning "...
A comma can be used to separate clauses in the same sentence. It doesn't always go after the word "therefore". One of the most famous quotes containing the word is:
I think, therefore I am.
"Therefore" is a conjunctive adverb that you can use as a transition word in sentences and paragraphs. In your example, it begins a sentence, so there must have been ...
You're right to wonder what they're talking about.
Here's what they're trying to point out. In this sentence:
Now that I'm married, I don't go out in the evenings so much.
the word now introduces a subordinate clause: "I'm married". The phrase now that functions like "because" (also a conjunction). In British English, people sometimes drop the that, but ...