That was the reason(that /which/不填 )Mac give us the other day.
这是一句定语从句
先行词【reason】在从句中作宾语
Mac give us 【the reason】the other day.
所以填上面三个
That was the reason(that /which/不填 )Mac give us the other day.
这是一句定语从句
先行词【reason】在从句中作宾语
Mac give us 【the reason】the other day.
所以填上面三个