i am sure they are nice. ;) glasses are plural in English so you need to say: "These glasses are nice." or " This pair of glasses is nice." ;) There are some other names in English like glasses, like: scissors, pants, trousers....

Actually, I didn't explain that very well, did I. Really it is different for drinking glasses, and a pair of reading glasses, because you can have one glass that you drink out of, and a pair of glasses that you see through is only one. Maybe that can explain it better.

The best answer is the second 1 because the word "these" is intended only for plural nouns and "this" is only for singular nouns. And for additional info., singular nouns use "is or was" and plural nouns use "are or were". So the correct sentence would be the second. I hope this would help you in choosing the best answer. Thank you.

it's the same whether you are talking about drinking glasses or glasses that you wear to improve your eyesight. as everyone here has said, these glasses are nice, which can either mean a pair of reading glasses (one only), or drinking glasses, in which case, there are more than one. "It's a nice glass of water", or "they are nice glasses of water". Sorry, the English language sometimes uses the same word to describe different things.

You have two pieces of glass in a pair of glasses: the lenses. Therefore, you treat glasses as plural. "These glasses are nice."