They decided to turn to can help them out of difficulty.
He likes the birthday presents ______ his friends gave him.
Upon ______ the office, he saw the message on his desk.
— Where’s Emma?—I can’t say for sure where she is, but she _____ be out shopping.
I always take an umbrella to work with me in spring, _____ it rains.
________ is known to everyone, the moon travels around the earth once every month.