New Words：

plus [plʌs] 加;和
minus [ˈmaɪnəs] 减;减去;零下

Sample Sentences：

Two plus five is seven.
Two plus five makes seven.
What's seven plus nine?

Seven minus three is four.
Nine minus five leaves four.
The temperature is now minus 10 degrees.
The temperature went down to minus ten last night.

New Words:

vaccine [ˈvæksiːn] n.疫苗
flu [fluː] n.流行性感冒;流感

Sample Sentences：
We need to use the new vaccine.
The world is still waiting for the birth of a new vaccine.

Is the flu vaccine safe?
I was stuck at home with flu.
How much do you know about bird flu?

New Words：

mean [miːn] v.表示…的意思;意思是;本意是

Sample Sentences：

I know what you mean.
What do you mean, bro?
What does this sentence mean?
The red light means (that) you must stop.

New Words：

secret [ˈsiːkrət] adj.秘密的;保密的. n.秘密;机密

Sample Sentences:

Can you keep a secret?
I want to tell you a secret.
What's the secret of your success?
Write down the secret place on the paper.

New Words：

splash [splæʃ] 泼洒;哗啦哗啦地溅;噼里啪啦地落

Sample Sentences：

Stop splashing me!
Water splashed onto the floor.
My clothes were splashed with mud.
He splashed cold water on his face.
He splashed his face with cold water.