下列说法正确的是（ ）
| A．在元素周期表中，每个纵列的价电子层的电子总数一定相等 |
| B．在元素周期表中，s区，d区和ds区的元素都是金属 |
| C．可能存在核外电子排布为1s22s22p63s23p64s24p1的原子 |
| D．在氢原子的基态电子的概率分布图中，小黑点的疏密程度表示电子在该区空间出现概率的大小 |
The student on duty should hand out the exercise books before class.
A．give outB．put upC．hand inD．take out
Mrs.Green will take her son to the amusement park if she ________ the tickets.
A．gotB．getsC．is gettingD．will get
All customers ________ to take their temperatures when they enter the supermarket.
A．is askedB．was askedC．are askedD．were asked
Not only Peter but also his father ________ crazy about the basketball match.
A．amB．isC．areD．be
—Bob，please ________ your spelling.You've dropped the "d" in the word "knowledge".
—Oh，yes.I'll be more careful next time.
A．listen toB．look forward to
C．pay attention toD．get used to