我是加拿大人,前英语老师.
不是这样的.
to 和 接下去的 3 个单词 be trifled with 不可连起来当作不定式去看.
词组
is to
are to
was to
were to
相等于
must ,
也就是说
This problem is not to be trifled with
和
This problem must not be trifled with
是一样的.