...的演唱比以前要动听许多。不明白句子中than he has before的时态。按理说,这里的 than he has before 应该是than he has sung before的省略,但无论从哪方面来看,这都有问题:从主句时态sang来看,than后面的时态应该是过去完成时,所以应...
•We can offer you refunds if the goods you returned are not dirty and unusable.•You can get refunds if the goods you returned remain clean and usable.请问这两句话中 if 后的时态是否正确?
Einstein said that if all our bees disappeared, man would only live for four more years!请问①宾语从句中,如果从句又是复杂句,时态怎么判别? 后面的从句以及主句,受不受said的影响?② 本句中的if从句,在这里属于虚拟条件句吗?