怎么才能看出when开头的句子是疑问句还是引导时间状语从句？

Question

如题所述

Answer 1

When
开头的句子是[疑问句],
后必须加[助动词]
：be,
have,
has,do,
does,shall,
did,
will,
should,
would
等.
When
is
Tara
coming?
塔拉甚么时候来？
Do
you
know
when
she
will
arrive?
你知道她甚么时候到吗？
When
did
you
hear
about
it?
你甚么时候听到这消息的？