世界上每天一定有地方下雨,属于确定事件中的必然事件;
故答案为:A.
The old furniture is made of _____. Please keep it away from fire. [ ]
A. glass
B. metal
C. wood
D. cloth
为了减少污染,一般选择培养材料的大小在0.5-1cm之间。