They usually ()(run)for half an hour every morning.

问题描述:

They usually ()(run)for half an hour every morning.

首先这个句子缺少动词,every morning是一般现在时的标志,所以添run

要用run。因为这个空要用动词的谓语形式,running是动词的-ing形式,非谓语形式。 run run run 就填原形run,因为这个句子是在陈述一个

run