It was not until 1911, _______ the first vitamin was identified, _______ people realized the importance of it.
---- Is everything clear now? ----Yes, the thief has admitted _________.
Peter has many friends,______can help him .
He is always helping people without expecting anything________.
------Shall I give you a ride as you live so far away? ------Thank you,________.
There might be life on other planets, but so far scientists haven't found enough ________ to prove it.