He has just had his breakfast and he _____ (leave) for school.

He has just had his breakfast and he _____ (leave) for school.
He has just had his breakfast and he _____ (leave) for school.

He has just had his breakfast and he _____ (leave) for school.
is leaving

前面说刚吃完饭，所以应该是“即将动身去学校”，这里的is leaving 是现在进行时态的形式，但是表示的是即将发生的动作，即一般将来时态。
正解

leaves ,,,,一般现在时表将来。
is leaving ,,,,