If someone .................... into the store, smile and say, 'May I help you?'
A.comes
B.came
C.will come
D.would come

We wondered why....................... a tip.
A.to leave
B.should we leave
C.we should leave
D.don't we leave

A.gulf
B.surface
C.submarine
D.current

A.poor
B.tour
C.actual
D.group

A.tiny
B.device
C.krill
D.migrate

A.investigate
B.information
C.submarine
D.independent

A.carnivore
B.entrapment
C.technology
D.Atlantic

Whales feed on krill.
A.tiny shellfish
B.small fish
C.sea plants
D.small animals

.................... is the variety of different types of plant and animal life in a particular region.
A.Interaction
B.Herbicide
C.Environment
D.Biodiversity

......................is a chemical used for killing weeds.
A.Pesticide
B.Herbicide
C.Fertilizer
D.Antibiotic