1.D
强调句型的一般疑问句.
原句为：It takes the man-made 48 hours which is made in our country to orbit the planet around.
即所谓的it takes sth some time to do sth,意思是“花费某物多少时间做某事”.
其中sth即the man-made satellite which is made in our country,其中which is made in our country为定语从句修饰the man-made satellite；
some time即48hours；
to do sth即to orbit the planet around.
对该句的48hours强调,即为：
It is 48 hours that it takes the man-made 48 hours which is made in our country to orbit the planet around.
其一般疑问句即为：
Is it 48 hours that it takes the man-made 48 hours which is made in our country to orbit the planet around?
此句即答案D.
2.B
不好意思,看花眼了,
逗号前后两句没有并列连词and等相连,且其中没有动词做谓语,说明后面既不是一个并列句,也不是一个非限制性定语从句,而是一个独立主格结构做句子的伴随状语.
排除使用关系代词whom引导非限制性定语从句的AC；
固定短语fix one's eyes on...,即fix和one's(their) eyes为动宾关系,反过来their eyes和fix为被动关系,所以使用其过去分词fixed做宾语补足语,排除D.
3.A
同样考查强调句型和定语从句.
强调句型的结构为：It is/was + 被强调部分 + that + 句子未被强调部分.
其特点是：去掉it is/was和that后,剩下成分可以构成一个完整的句子（有时需要调整句序）.
原句为：Playing computer games cost the boy plenty of time that he ought to spend doing his homework.
其中,that he ought to spend doing his homework为定语从句,修饰(plenty of) time,因为关系代词that代替time在定语从句中充当spend的宾语（即sb spend time doing sth）.
对该句的主语playing computer games强调,即为：
It was playing computer games that cost the boy plenty of time that he ought to spend doing his homework.