A.understand how to do something
B.sail along the area of water
C.find which way to go
D.surfing the internet for something

A.helping each other
B.working together
C.combining with each other
D.befriending with each other

A.do
B.make
C.deal
D.take

A.do
B.make
C.deal
D.take

A.Jim’s bike has been stolen yesterday.
B.Jim had someone steal his bike yesterday.
C.Jim’s bike is stolen.
D.Jim had his bike stolen yesterday.

A.My sister and I take turns washing my clothes.
B.I often have my clothes washed when my sister is busy.
C.My sister helps me wash my clothes when I am busy.
D.I often have my sister’s clothes washed.

A.carried
B.carry
C.to carry
D.been carried

A.study deep learning
B.release ultrasound
C.diagnose breast cancer
D.produce medical devices

A.dangerous
B.risky
C.safe
D.perilous

A.benefits
B.interests  
C.concerns  
D.disadvantages