A.secure
B.vacant
C.oblige
D.equip

They made an aerial survey; that is, they made a survey_________.
A.by ship
B.by plane
C.on foot
D.by telescope

Hummock grasses grow in loose sand on the crest.
A.side
B.bottom
C.top
D.inside

A.roughly
B.tough
C.enough
D.though

A.area
B.arise
C.arrange
D.arrive

A.circle
B.center
C.census
D.cancel

__________(49)
A.onto
B.up to
C.to
D.into

__________(46)
A.is proving
B.has proved
C.proved
D.had proved

__________(44)
A.artificial
B.synthetic
C.compound
D.man-made

Choose the best answer A, B, C or D to complete sentences.
She likes to study................ at university.
A.economy
B.economic
C.economics
D.economical