Question

英语中什么是主系表结构？另外什么是系动词？什么是表语。

Answer 1

is
are
was
were都是系动词，this
is
a
cat.这是主系表结构，系动词后的宾语叫做表语。

Answer 2

举个例子I
am
a
teacher.He
is
a
worker.You
are
a
student.这是简单的主系表结构。am
is
are就是系动词。teacher
worker
student就是表语。