it is in beijing __ the 2008 olympic games will be held为什么要用that?而不用which?where?

it is in beijing __ the 2008 olympic games will be held为什么要用that?而不用which?where?
it is in beijing __ the 2008 olympic games will be held
为什么要用that?而不用which?where?

it is in beijing __ the 2008 olympic games will be held为什么要用that?而不用which?where?
因为是强调句.强调句的特点是,去掉句子结构（it is...that...)原句子还能保持完整
去掉以后就是 in Beijing the 2008 Olympic games will be held.调换下句序就是the 2008 Olympic games will be held in Beijing.

这个是强调句，强调句的形式是It is...that...

这是强调句，句型是“It is(was) + 被强调部分 + that(who) + 从句”。
其特征是去掉It is(was)和that(who)之后,剩下的部分仍然可以作为一个完整的句子。
这句话的原句应该是In beijing the 2008 olympic games will be held.