[译] 我惩罚她的原因是因为她偷了我的钱。
[误] The reason why I punished her is because she stole my money.

[正] The reason why I punished her is that she stole my money.
[注] 表示"……原因是因为……"，应该说 The reason why...is that...，即表语部分应是由 that 引导的名词性从句, 不可以用连词 because 引导。