So difficult __________ it to work out the problem that I decided to ask Tom for advice.

Bruce，I really appreciate yourhandwriting.—________.

Of the two T-shirts，I’d choosethe ___one to save some money for a book.

Mary，I don’t know ____ you can come tomorrow morning. —No problem! I’ll be here _____I’m free then.

Steven, we should ______ the bus at the next stop.