结合句意和语境可知选A。
点睛：限制性定语从句中只能用that引导定语从句的几种情况：
当先行词是everything, anything, nothing（something除外）, all, none, few, little, some等不定代词时，或当先行词受every, any, all, some, no, little, few, much等词修饰时。如：
【点睛】
在定语从句中，当先行词是人时，引导词在定语从句中做主语时，引导定语从句的先行词用that或who，引导词在定语从句中做宾语时，引导定语从句的先行词用that或whom，引导词前面有介词时，必须用介词whom。例如，（1）The girl who is singing an English song in the next room is Tom’s sister.（2）The person that/whom you talked to just now is Tom’s father.=The person to whom you talked just now is Tom’s father.
Wang Hua is the only person in our school who will attend the meeting. 5.当先行词前面有who, which等疑问代词时。如：Who is the man that is standing in front of the crowd?站在人群前面的那个人是谁？Which is the room that Mr Wang lives in?哪一间是王先生住的房间？
当先行词人与物时。如：Look at the man and his donkey that are walking up the street.
当先行词是reason, way（方法）等词时，关系代词常用that代替in which, for which, why,也常可省略。如：She admired the way（that）they solved the questions.
在定语从句中，当先行词和后面的名词是所属关系时，用whose引导此定语从句。例如，They lives in a room whose window opens to the south.他们住在一间窗户朝南开的房间里。
4．Mr.Brown is a teacheris strict with all is students.
2．﹣Look！This is the photoI took in Beijing World Gardening Expo（世界园艺博览会）in 2019．
﹣Wow，so great！
A．whatB．whoC．whereD．that
【答案】D
【解析】
【详解】
句意：—看！这是我2019年在北京世界园艺博览会拍的照片。
3．A true friend is a person ________ reaches for your hand and touches your heart.
A．whomB．whoseC．whoD．which
【答案】C
【解析】
【详解】
句意：真正的朋友是一个帮助你并且让你感动的人。考查定语从句的关系词。本句中先行词person为定语从句的逻辑主语，且指人，所以引导定语从句的关系代词用that或者who；结合句意和选项可知选C。
在定语从句中，当先行词是物时，引导词在定语从句中做主语时，引导定语从句的先行词用that或which，引导词在定语从句中做宾语时，引导定语从句的先行词用that或which，引导词前面有介词时，必须用介词which。例如，He was reading a book which/that was about war.他正在读一本关于战争的书。
考查定语从句的关系代词，what不用在定语从句中，who先行词为人，在从ቤተ መጻሕፍቲ ባይዱ中作主语或者宾语，where先行词为地点，在从句中作状语，that先行词为人或物，在从句中做主语或宾语，the photo为先行词，从句中缺宾语，句意理解为﹣﹣看！这是我2019年在北京世界园艺博览会上拍的照片．﹣﹣哇，很不错．故选D。
中考专项训练定语从句难题及答案
一、定语从句
1．This is the most beautiful picture __________ I have ever seen.
A．thatB．whichC．whatD．who
【答案】A
【解析】
句意：这是我见过的最漂亮的画。考查定语从句。先行词被最高级修饰时，引导词应用that。
Have you set down everything that Mr Li said? There seems to be nothing that is impossible to him in the world.注意：当先行词指人时，偶尔也可用关系代词who。如：Any man that / who has a sense of duty won’t do such a thing.任何有责任感的人都不会做这样的事。All the guests that / who were invited to her wedding were important people.所有被邀请参加婚礼的客人都是重要人物。2.当先行词被序数词修饰时。如：The first American movie that I watched was the Titanic. 3.当先行词被形容词最高级修饰时。如：This is the best museum that I have visited all my life. 4.当先行词被the very, the only, the first / last等修饰时。如：She is the only person that understands me.注意：当先行词指人时，偶尔也可以用关系代词who。如：