砌筑砂浆用外加剂应符合国家现行有关标准规定,()外加剂还应有完整的型式检验报告。
A.减水剂
B.引气型外加剂
C.增稠剂
D.早强剂
参考答案:B
用所给词的适当形式填空
1. Lucy’s father ______ ______ (want) ______ ( is) an actor.
2. My best friend Susan ______ (like) thrillers but she ______ ______ (not like) comedies.
3. Jet li is a ______ (success) movie actor.
4. The book is very ______ (interest). Everyone is ______ (interest) in it.
5. Beijing Opera is ______ (real) fun.
6. I want to learn ______ ______ (play) basketball from YaoMing.
7. ______(she) favorite fruit are bananas.
8. Do you want to play sports with ______ (I).
9. There are all ______ (kind) of books in this library(图书馆).
10. My daughter wants me ______ ______ (take) her dictionary to school for her.
(4分)请根据以下材料,回答下面的问题:
人类的能卷舌是由显性基困决定,用R表示,不能卷舌是由隐性基因决定,用r表示,小明的祖父、祖母能卷舌,父亲也能能卷(Rr);小明的母亲不能卷舌(rr)。试根据遗传过程图解回答下列问题:
(1)写出卵细胞②的基因组成_________,小明的祖父、祖母能卷舌,父亲也能卷舌,遗传学上把这种现象叫做 。
(2)小明是单眼皮,若他的父母再生一胎,是单眼皮的几率是____________ 。
(3)如果R为正常肤色基因,r为白化基因,那么此人的性状表现为肤色正常,如果要确保此人的后代没有白化子女出现,有效的预防措施是___________________。