A:{a=2b=1
B:{a=2b=−3
C:{a=52b=1
D:{a=4b=−5
- It's one of the things in the world to stay with friends.
- I agree. It always makes us relaxed.
全天的播音时间共有____
一个凸透镜的焦距是20cm,若将一物体放在此透镜前30cm处,可在凸透镜的另一侧得到一个( )
-- It's snowing. I really want to run outside and make a snowman.
-- Why not have a snow ball fight instead? It's more exciting.