A:π2 +1
B:π2 +3
C:3π2 +1
D:3π2 +3
Most Americans don't like to get advice from members of their family.
读我国四大区域图(如图,B图为丙地气候资料),据此回答下列问题.
已知1个水分子的质量约为3×10﹣26kg,又知4℃时,水的密度约是1g/cm3.大约22滴水为1mL,则一滴水里大约有多少个水分子?.