Mr Black, this is our language labWould you like to go in and have a look– OK

The cost of organic food is higher than _____ of conventional food because the organic price tag reflects more closely the true cost of growing the food．

They ______trouble lifting the heavy box. [ ]

It is natural for children to be naughty sometimes. Try not to get so ___with them. [ ]

Every boy and every girl as well as some teachers who ___ to visit the museum _____required to be at the bus station at 6:30.