It was a present ______ my father bought for me yesterday.这句

It was a present ______ my father bought for me yesterday.这句是定语从句还是强调句型?

是定语从句,a present是表语,后面的空格填which,which引导的从句起的作用就是修饰 a present
从句的类型是由从句的位置或者说从句起的作用决定的.从句放在宾语的位置、起宾语的作用就是宾语从句；放在名词/代词之后、起定语的作用就是定语从句（修饰名词/代词的词叫定语,修饰名词/代词的从句就叫定语从句）.
eg:I don't know why he was late.我不知道他为什么迟到了.(why he was late放在了know之后,占了动词know的宾语的位置,所以叫宾语从句.）
I don't know he reason why he was late.我不知道他（为什么）迟到的原因.（why he was late放在了the reason之后,是用来修饰the reason的,也就是the reason的定语,所以叫定语从句.）
再问： 为何不能理解为对宾语a present 进行强调呢？去掉it is....that ......还是一个结构，意思都完整的句子啊。不是吗？
再答： 如果你改成 It was the present that my father bought for me yesterday. 那就是强调句型。 下面和你说一下定语从句和强调句型的区别： ◎强调句中的It没有实际意义，It be与that可同时被省略；而定语从句中的It是主语，It be与that不可同时省略； ◎强调句型中be的时态须跟后面句子的时态相一致；而定语从句中主句谓语动词be的时态须由主句的时间确定 ◎强调句将句子中的that不能省略，并且即使前面的名词是事物时，也不能将that换成which；而定语从句中的that作宾语时可被省略，并且当先行词是事物时可用which代替。 ◎当it be后面的时间、地点名词作主语、宾语或表语时，引导词可用that / which；而作其他成分时，引导词须用when / which。如： (1) It is an English book (that / which) I bought yesterday. 它是我昨天买的书。(本句是对What is that?问句的回答，that所引导的是定语从句，that可被省略) It was the English book that I bought yesterday. 昨天我所卖的就是这本书。(本句相当于对I bought the English book yesterday中an English book进行强调) (2) It was a room where we used to have meetings. 它是我们过去常在开会的房子。(where 所引导的从句对前面的room进行说明，它是定语从句) It was in the room that we used to have meetings. 过去我们开会就在这间房子里。(in the room是被强调的部分，本句是强调句型) (3) It is a day when the people celebrate their victory. 这是人们庆祝他们的胜利的日子。 (when所引导的从句对a day进行说明，是定语从句) It was on that day that people celebrated their victory. 就在那一天，人们庆祝了他们的胜利。(强调on October 1, 1949)