Some scientists think that it will take __ of years to make robots do most work for humans.
A. hundreds B. hundred C. thousand
My cousin knows a lot about geography, __ he is only four years old.
A. because B. so C. although
--Hey, Tony, You look so tired today.
---I __ until 12 o' clock last night for the math test.
A. woke up B. stayed up C. grew up
Look! PeterTV happily, but his parents are busy in the kitchen.
A. is watching B. watches C. watched
Parents often ask their kids __ their internet friends because the kids may be in danger.
A. to meetB. not to meetC. meeting