Yes, it is an adverb of indefinite frequency.
It's an adverb of time.
Only verbs have tenses (in English), and the word usually is an adverb. It has no tense.
Phrasal adverb
Yesterday is an adverb. It answers "when" something was done or happened.
memorized
No, it is an adverb of time. It refers to a frequency (less than often), or not usually.
"Usually" is an adverb that is commonly used to indicate something that happens most of the time or under normal circumstances.
Sometimes is an adverb, an adverb of frequency.
Usually is an adverb of frequency.
No, usually is an adverb.
It can be, and usually is. In sentences such as "Let's get together sometime" it is an adverb of indefinite time. More rarely, as in "He was a longshoreman and sometime wrestler" it is an adjective.
No, it is not a preposition. Usually is an adverb.
"Usual" is generally an adjective.For example, you can put it in front of a noun to add description:I caught the usual bus.She was wearing her usual smile.Like other adjectives, "usual" may be used without a noun, and appear to be a noun:What would you like today? The usual?
An adverb of place does not really have to come after an adverb of time.
Yes, tonight is an adverb. It is an adverb of time (point in time).
No, it is an adverb of indefinite time. This is another type of adverb of time.
In the example sentence, the word 'usually' is an adverb, modifying the verb 'is' (is how often).The word 'by' is not in the sentence, but the word 'by' functions as a preposition, introducing a prepositional phrase; for example, 'by the time he gets home' ('by the time' is a prepositional phrase).The word 'by' also functions as an adverb, for example, 'Please stand by.' (the adverb 'by' modifies the verb 'stand).