Mary works in a bank. She is ____ busy every day that she____ no time to make dinner. There is a(n)____near Mary's house. After Mary comes back home from work, she likes to go to the restaurant____dinner.

    One day,____ Mary was in the restaurant, she saw____old man next to her looking for (寻找)something on the floor(地板).Mary felt surprised. So she____the old man.

    "____are you looking for?"

    "Oh, a piece(块)of bread," the man answered.

    "A piece of bread? Oh, the floor is so____.Please take this piece." Mary gave(给)a big piece of bread to the old man.

    "But my teeth____in that piece of bread."

如图，直线a∥b，直线c是截线，如果∠1=50°，那么∠2等于（　　）