刘敏同学在化学课上提出,可用澄清石灰水来检验人呼出的气体是否含二氧化碳,就这一过程而言,属于科学探究环节中的( )
A.做出结论
B.收集证据
C.设计实验
D.建立假设
答案:C
Tom’s parents were very worried because ___little effort he made could hardly achieve the goal to be
___ captain of the team. [ ]
A. a; the
B. the; /
C. /; /
D. a; /
可取性启发式