直线上两点间的部分叫做______.有一个端点的直线叫做______.
直线上两点间的部分叫做线段.有一个端点的直线叫做射线;
故答案为:线段,射线.
Jane was disappointed that most of the guests_______when she _____at the party.
A.left; had arrived
B.left; arrived
C.had left; had arrived
D.had left; arrived
设nA为阿伏加德罗常数的数值,下列说法正确的是
A.常温常压下,8gO2含有4nA个电子
B.1L0.1mol·L-1的氨水中有nA个NH4+
C.标准状况下,22.4L盐酸含有nA个HCl分子
D.1molNa被完全氧化生成Na2O2,失去个2nA电子