When I got into the office, I found Mr. Green ____ in his work, without noticing my arrival.
It is usually warm in my hometown in March, but it ________ be rather cold sometimes.
You can never be ________ when crossing the street.
________, you need to give all you have and try your best.
Before Sally left home, her mother kept telling her to ________ her manners at the party.
She has ________ that I find it hard to believe anything bad of her.