Question

关于宾语从句的问题？

It is a good manners to eat up what is left in your plate.

it是形式主语，is是系动词，a good manners是表语，为什么what引导的是宾语从句呢？已经有is了，难道不定式to eat up又做谓语？

Answer 1

“to eat up what is left in your plate”是用来补充说明“is a good manners”的系表结构的；
故其“to eat up what is left in your plate”不是宾语，不是谓语，不是状语，不是主语，不定语，所以只能是补语。

正所谓，to-动词不定式用来补充说明。

而”what is left in your plate“正是用来接那个动词“to eat up”，作后者之宾语，故曰其宾语从句。

Answer 2

what is left in your plate 是动词不定式eat up的宾语从句，汉义：吃光你盘子里所剩下的东西。

追答

to eat up what is left in your plate 是动词不定式短语作真正的主语。
全句话汉语意思：吃光你盘子里所剩下的东西是一种好的举止。

如还有疑问，欢迎追问，有问必答！

Answer 3

who
do
you
think
is
the
best
student
in
our
class
？改为宾语从句
是改成
do
you
think
who
the
best
student
is
in
our
class
？---才对。
但是此句子句式是不同的哦。
who
（do
you
think
i）s
the
best
student
in
our
class
？括号里是插入语，而你后面do
you
think
who
the
best
student
is
in
our
class
？--的do
you
think
不是插入语哦。
do
you
think
who
the
best
student
is
in
our
class
？---这句话是对的。但是并不是who
do
you
think
is
the
best
student
in
our
class
？改成的宾语从句。
我们只是把主语和谓语动词换一下位置而已，而不是要把后面in
our
class状语都提前。