请老师分一下这个句子的三种时态,尤其是后两个谓语动词部分为什么一个用完成时一个不用?He (has written) several novels since 1985.
Most of them (have been) very
successful, but the last one (didn't get)
very good reviews.
The World Health Organisation declared Liberia free of Ebola, ending an outbreak in west Africa which has killed more than 11,000 people. 如何理解句中的 ending 和 which?
The confederacy has stood unchallenged in its supremacy over colonized space.如果这里的stand表示“处于...的状态”,那后面似乎应该是at its supremacy,而不是in its supremacy才是固定搭配不是吗?