D．Look after children and keep house.

　　D　解析：细节理解题。根据第三段第二句"She knew it would be hard work raising three kids, doing housework and studying at the same time．"可知，母亲在学习的同时还要照顾孩子、做家务，故选D。

　　3．According to the text, the author's mother ________.

　　A．recovered from illness

　　B．no longer had faith in God

　　C．didn't realize her dream as a teacher

　　D．changed negative situations into positive ones unwillingly

　　C　解析：细节理解题。根据倒数第二段最后一句"My faith in God just disappeared and so did my mom's dream of becoming a teacher．"可知，母亲因为患病，成为教师的梦想破灭了，故选C。

　　4．Which of the following is the best title for the text?

　　A．Fighting Against Kinds of Diseases

　　B．Mother Gave Me Life Experience

　　C．Belief in God Brought Me Good Luck

　　D．How to Become a Responsible and Active Man

　　B　解析：标题归纳题。根据对文章的整体理解可推知，本文主要讲述了乐观的母亲对作者的积极影响，作者由此成为了一个积极面对生活的人，故选B。

　　B

　　(2019·太原一模)Researchers are now using three­dimensional(三维的), or 3D printing to create models of the human heart to help heart specialists. The heart doctors can use the models to better help patients before an operation.

　　Surgeons regularly use digital images to explore the heart in close detail. But no two human hearts are alike. This leads Matthew Bramlet, a children's heart expert, to create exact heart models from those images. He says the 3D models show information he cannot get in any other way. The 3D printed model adds a new dimension to heart surgery, allowing surgeons to see defects that might not be readily apparent in digital images.

A 3D printer uses images from a digital display to create a physical model of a human heart. Pictures from medical tests like a CAT scan or an MRI scan are sent to a 3D printer to create a heart in a plaster or a clay form. The printer then constructs the heart, a thin layer by a thin layer. Dr. Bramlet says the model matches the real heart in every detail.