Question

The world's population has grown to more than six times____it was in 1800. A.that B.what C.which

Answer 1

你好！
这是一个主句和一个从句的关系，主句The
world's
population
has
grown
to
more
than
six
times，从句it
was
in
1800，单看从句，句子完整不缺成分，肯定就不能选that/what/which，只有选一个时间状语。所以选when
希望对你有所帮助，望采纳。

Answer 2

选择B项，主要是当你问人口有多少的时候，我们会运用What
is
the
population？句子中it指的是the
world's
population,整句话的意思：与公元1800年的人口相比，现在的人口是原来的六倍多。

Answer 3

The
world's
population
has
grown
to
more
than
six
times
what
it
was
in
1800.
答案是B
目前的世界人口与1800年相比已经增长到那时的六倍多！
短语grow
to意思是“增加到”。类似的表达法还有increase
to,
rise
to,
climb
to等。如：