答案是B,正确.
句意：是在她生日那天她父母给她的dv做礼物吗?
填when不对,如果题中的on her birthday改为her birthday,此题就选择when.
规律方法：
1.如果你看到it作主语,首先想到是强调句型,而且有一个检验方法.把it is……that……这个结构去掉,原句子还成立,那么就是强调句型.本必须使用that.题中,你试一下,去掉,剩下：on her birthday her parents gave her this dv at present.是一个完整句子.所以是强调句型.
2、when也有一个相似句型,it was +时间点+when+句子.这和强调句型的区分,就依靠以上提到的检验方法.
看以下的例子：
it was Sunday when he arrived.
It was on Sunday that he arrived.
如果不懂,欢迎你提交讨论.如果还有其他疑问,可以去“状元365”提问.