应当填 is planting,本句缺少谓语,因为at the moment所以用进行时.with,together with,along with 谓语单复数应当以所修饰的名词为准.at the moment不是也可以用过去式吗？你说得有道理例如：He is busy at the moment 他此刻很忙。At the moment he was busy preparing his lessons . 那时，他正忙于准备功课at that moment 强调在那时，that代指前后文提到的时间所以本句填was planting 也可以。