问大神，两个并列的动词，时态必须一致，还是可以不一致？My Trigonometry teacher, Mr. Varner, who I would have hated anyway just because of the subject he taught, was the only one who made me stand in front of the class and introduce myself.这里introduce为什么会用现...
...ually it is (was) pretty good.这里用is还是was, 前面部分是过去时态，如果用现在时态is表达这个电影本身很好的事实是否可以？2) I came (was coming) to visit you later that day, but I had to phone and cancel.had to phone and cance在句中是什么意思？动词...
I've never had such a thing happening to me before . 向老师请教个问题, 整个句子时态是从"过去一直到现在",但句末却有个"之前",这时如果happening to me 改成从句,该用什么时态 which happened 还是which happens?
there are many new buildings which have been constructed in this citythere have been many new buildings which have been constructed in this city老师，这个句子 蓝色部分的不同时态，所描述的情况是什么样的
我找到两种说法，一是时态不变,例句：Scientists discovered that DNA holds the code for life.一是时态可变可不变，例句Copernicus proved that the earth goes/went round the sun.请问如何理解这两个句子？
Many of the reductions over the past 30 years have been achieved either
by reducing the amount of sugar, salt or fat in a product, or by finding
an alternative ingredient.这个句子have been achieved是什么时态
The list included most of the things Hugh loves: butter, potatoes, rice, beer, milk, chocolate，and sweets. 如果主句是一般过去时态，从句常用过去的某种时态；这里时态为什么不一致？为什么用loves而不是用过去时？