New words：
wander [ˈwɑndər]
n.徘徊；游荡；闲逛；溜达
v.漫游；游荡；闲逛；走神
Sample Sentences：
Try not to let your mind wander.
Jarvis found his attention wandering.
Her thoughts wandered back to her youth.
I went to the park and had a wander around.
When he got bored he wandered around the fair.
The child was found wandering the streets alone.
New words：
challenge [ˈtʃæləndʒ]
n.挑战；质疑
v.向(某人)挑战；考查；盘问；对…怀疑（或质疑）
Sample Sentences：
He raised a challenge to the decision.
This math problem is a challenge for most students.
The teacher gave us a challenge to read 10 books this month.
Tom challenged me to a race after school.
The police challenged his ID at the airport.
Their school challenged ours to a football match.
I don't have the courage to challenge my boss's decision
New words：
record /ˈrekɔːd/ n.记录；唱片；记载；经历
Sample Sentences：
She loves listening to jazz records.
The police checked his criminal record`.
His sports record includes many awards.
She broke the world record in swimming.
The school has a record of all students’ grades.
New words：
record /rɪˈkɔːd/ v.记录；录制；记载；录（音）；（仪器）显示，标明
Sample Sentences：
The thermometer recorded 38°C.
The device records the speed of the car.
She recorded her daily thoughts in a diary.
I want to record my favorite radio program.
They recorded a video message for their grandma.
The teacher asked us to record the experiment steps.
record /ˈrekɔːd/ n.记录；唱片；记载；经历
New words：
millimetre [ˈmɪlɪˌmitər] n.毫米；千分之一米millimeter [ˈmɪlɪˌmitər] n.毫米；千分之一米
Sample Sentences：
One centimetre equals ten millimetres.
These jellyfish were only one millimetre long.
Brisbane recorded 790 millimetres of rain in a week.
The land moves northwest by four millimetres per year.