21.

  1. Bert's sister.
  2. Bert's mother.
  3. Bert's wife.
  4. Bert's friend.

(Click to show or hide the key.)

22.

  1. They were always short of time.
  2. They were very forgetful.
  3. They were very frightened of flying.
  4. They often suffer from airsickness.

(Click to show or hide the key.)

23.

  1. A stamp.
  2. An envelope.
  3. Two tickets.
  4. Some flight insurance.

(Click to show or hide the key.)

24.

  1. An empty envelope.
  2. Some coins.
  3. The tickets.
  4. The insurance policy.

(Click to show or hide the key.)

25.

  1. He had to do everything in a great rush.
  2. It was his first flight, and he was very worried about it.
  3. He had forgotten to bring a stamp for his mother's letter.
  4. He was very worried about his mother.

(Click to show or hide the key.)

Let me tell you a story about Bert and Mildred Bumbridge, who used to be very forgetful. For example, Mildred would forget to cook dinner, or Bert would show up for work on Sunday thinking it was Monday. One summer they were to take a long plane trip. What do you suppose happened? Well, they got to the airport with only ten minutes to spare. So time was short. In that situation anyone would board the plane right away. But not Mr. And Mrs. Bumbridge. They just had to buy some flight insurance first. After all, who knows what will happen on a plane flight? They quickly put some coins into a machine and out came their insurance policy. "Who would get the money if we crash, I wonder?" asked Mildred. "My mother, of course," her husband replied. "We'll mail the policy to her. Now quick, give me a stamp, will you?" he said. "The plane's going to take off in another minute." Bert put the stamp on the envelope, dropped it in the mail box, and suddenly let out a cry. What happened, do you suppose? He had mailed their plane tickets to his mother!