组织培养中进行细胞纯化时可以采用下列哪一种实验技术( )
A.细胞克隆技术B.细胞筛选技术C.细胞蚀斑技术D.有限稀释法E.无限稀释法
参考答案:A
阅读下面短文,写出括号中所给动词的正确形式,使短文意思完整。
My mother is very kind and easygoing, she helps me a lot. I 1_______ (take) good care of in my daily
life by her. When I'm in trouble, she always 2_______ (encourage)me to face my difficulties. I still remember
that once I 3______ (argue) with my best friend. My mother talked with me the whole night and finally helped
me solve the problem. With her help, I 4_______ (become) a top student in my class already. I believe she
5_______ (be) proud of me in the near future.
麻痹性痴呆,通常在梅毒感染后__________年内出现。发生痴呆时可有多种症状,如欣快、幼稚的自夸和__________等。