Our hometown is more beautiful than before,.Swimming in the pool with friends_very interestingA;has B;have C;is.Some of my classmates_from other citiesA;comes B;is C;areThis is my twin sister Lucy.Both she and I_good at drawing.A;am B;is C;areThe professor,together with his son,_Lanzhou_BeijingA;have left;for B;has left;for C;have left;toMy family_having supper when suddenly the bell rangA;is B;was C;wereThe singer and dancer_come to our schoolA;have

1. C 动词ing做主语 后面有一个interesting 是一个形容词  be 动词加形容词  构成系表结构
   

2. C;are   Some of my classmates 是指 我的一些朋友  复数形式 词组  be from 来自于

3.    C;are    both....and ..为 两者都  复数形式  用be 动词are

4. B 真正的主语为The professor, 一人  而together with his son,只是一个附带  也可以放在后面

5. C;were  My family为我的一家人  复数形式

6. A;have   现在完成时  主语为两个人  谓语动词用have原形  

7. A;is waiting    A number of children   谓语动词要用复数形式

8. A;has    强调每一个  用单数

希望帮到你  望采纳！！

C.is
C.are
C.are
B.has left,for
C.were
B.has
B.are waiting
B.have

Our hometown is more beautiful than before,（isn't) it?
这是反义疑问句.
Swimming in the pool with friends （C） very interesting.
A;has B;have C;is
“Swimming in the pool with friends ”指一件事,为单数.is+interesting形成系表结构.
Some of my classmates （C） from other cities.
A;comes B;is C;are
“Some of my classmates”我的一些同学,为复数,使用are
This is my twin sister Lucy.Both she and I （ C ）good at drawing.
A;am B;is C;are
Both……and……谓语用复数形式.
The professor,together with his son,（ B ）Lanzhou_Beijing.
A;have left;for B;has left;for C;have left;to
The professor主语为单数,together with his son只是一个插入语
My family（ A） having supper when suddenly the bell rang.
A;is B;was C;were
My family我的家人（我们一家）,作为一个整体.
The singer and dancer （A） come to our school.
A;have B;has C;were
and并列singer 和 dancer ,为复数,谓语用have
A number of children （B ）for the teacher to come now
A;is waiting B;are waiting C;waits
A number of大量的……,谓语用复数形式
The students each （A ）a dictionary now.
A;has B;have C;has got
each 每个人,所以是单数.
如有不懂,再行探讨,