How long is it since your father

网友回答

填became.
since表示“从（过去某个时间起）.（到现在）”,后面跟某个过去的动作或过去某个时间点.
例如：It is two years since I came here.从我来这里,已经过了两年了.
I have been living here since 2002.从2002年我就一直住在这里.
======以下答案可供参考======
供参考答案1:
became
注：since 后的动词要用一般过去时
加油！不明白再问！如果帮到你，请采纳，谢谢！
供参考答案2:
How long is it since your father (became) an engineer.
供参考答案3:
became.
用过去式，从成为工程师开始
供参考答案4:
became
是since 后面用过去式