______ the earth to be flat, many feared that Columbus would fall off the edge of the eart
A.Having believed
B.Believing
C.Believed
D.Being believed
A.Having believed
B.Believing
C.Believed
D.Being believed
A.What in earth
B.where in earth
C.What on earth
D.Where on earth
Aluminum is found on earth mostly in the form. of______.
A.pure metal
B.bauxite
C.gold
D.liquid
The sun warms the earth, ______ makes it possible for plants to grow.
A.this
B.that
C.as
D.which
(That) the sun (but) not the earth (is) the center of our planetary system (was) a difficult concept to grasp in the Middle Ages.
A.That
B.but
C.is
D.was
The earth revolves a little more rapidly______it is closer to the sun.
A.whether
B.whereas
C.although
D.when
According to the passage, the earth in its very early period was ______.
A. in molten state
B. in water state
C. in rock state
D. a vast ocean
______with the size of the whole earth, the highest mountain does not seem high at all.
A.Compared
B.Compare
C.Comparing
D.While comparing
What's the author's attitude towards the waste of the earth's resources ?
A.Negative.
B.Positive.
C.Neutral.
D.Enthusiastic.