calm down，take a breath，be crazy about，let down，apologize to，concentrate on，help out，work out，communicate with，be filled with

（1）

Concentrate on

Concentrate on

the good things about the Internet.
（2）I have

been crazy about

been crazy about

this film since I first saw it on TV.
（3）In all those years he never worked hard，which

let

let

his parents

down

down

.
（4）In my opinion，parents and children should

communicate with

communicate with

each other and show respect for each other.
（5）The famous actor keeps fit by

working out

working out

for an hour every morning.
（6）If you keep a positive attitude，your life will

be filled with

be filled with

happiness.
（7）Hearing what Father had said，the crying child soon

calmed down

calmed down

.
（8）You must

apologize to

apologize to

your parents for being so rude.
（9）He is the person who

helped

helped

me

out

out

.
（10）A swimmer can't swim under water very long，because he must

take a breath

take a breath

.