I know nothing about the young lady ________ she is from Beijing.

Where did you get this book?—I picked it up from a second-hand bookshop if you ______ know.

to the Internet, we have_________ to data quickly and effectively, regardless of where we are and what we are doing.

Tom and I ________ good friends. He ________ twelve.

We know _____better and _____ the unfinished workof perfecting the union falls to each of its citizens.