"If you were to go to the store" is a clause that introduces a cause and effect relationship. Note that it is a hypothetical condition that requires the subjunctive mood of the verb "to be". The sentence could be finished with a condition that will occur as a result:
If you were to go to the store you would see that the turnips are on sale.
The use of "then" to join the two is optional.
Correct: "Go visit your nearest grocery store." Incorrect: You're is a contraction, meaning you are. It would be the same as saying, "Go visit you are nearest grocery store."
No, "they and I" is not grammatically correct. It should be "they and I" as the subject. For example, "They and I are going to the store."
No, "is go with" is not correct grammar. The correct structure would be "go with" without the word "is." For example: "The red shoes go with the blue dress."
"Few days to go June will be ended soon" is not correct grammar. The correct grammar is "June will end in a few days to come." or "A few days to go until June ends."
Do you mean: "Are there ways to correct grammar?" Well yes. You see, it's sort of like grading. If someone says something or their grammar incorrect, and you correct them, you are like sort of correcting their grammar and this is the only way to answer your question so.
You and your dad went to the store
No, "will be had" is not a correct grammar. The correct grammar would be "will have."
No, it is correct grammar, not a correct grammar.
The correct grammar is: "Are those correct?"
The one that is NOT a sentence fragment and uses correct sentence grammar is:He liked to go fishing.
"On a train" is correct grammar.
The correct grammar for this sentence is: "When did you send it?"