a subject
There is a good question. In this case, it is a preposition.
Yes, "however" can be used as a clausal opener to introduce a contrasting or concessive idea in a sentence. It is often followed by a comma when used in this way.
The first sentence in a paragraph. It givesm the reader and idea of what the paragraph/essay is going to be about.
Yes, an opener can be in the middle of a sentence as long as it is set off by punctuation such as commas. For example, "However, despite his efforts, he still did not succeed."
A pronoun opener introduces a pronoun in a sentence and helps avoid repetition of a noun. For example, in the sentence "Mary went to the store. She bought groceries," "She" is the pronoun opener that refers back to Mary without restating her name.
In most cases yes.
A prepositional opener is a type of sentence structure where a prepositional phrase is used at the beginning of a sentence to provide additional information or context. It can help set the scene or clarify the relationships between different elements in a sentence.
it is a 2nd class lever
what kind of car
It is often called "A Church Key".
What kind of question is this? No one.