老师你好，语法书里说'someone has gone to a place'means that he is in that place now.
'someone has been to a place' means that he went to that place,but now is back.
但是为什么'Joe and Lisa are on holiday in Japan.They've been to Japan once before.'可以说成'This is the second t...
At some intermediate PH called the isoelectric point, the protein molecule has no net charge. This can lead to attraction of protein molecules to each other resulting in loss of solubility, coagulation. and precipitation.中lead to是后面句子的谓语，attraction of protein molecules to e...
...在不断恶化。美国人仍然在开车时发短信、使用社交网络和拍照。多年来一直在下降的交通事故，现在正在急剧上升。 That
is partly because people are driving more, but Mark Rosekind, the chief of the
National Highway Traffic Safety Administration, said distr...
...了young people后面？ 2. Just the day before, a stranger ahead of her in line had generously paid
for her coffee.Just the day before是省略了介词吗？补充完整是不是Just at the day before？ 3. As in all of my races, I didn't start out in the front. I loved the
pleasure of passing p...
...d with courts of law. We might say that
justice has been done when a man's innocence or guilt has been proved beyond
doubt. Justice is part of the complex machinery of the law. Those who seek it
undertake an arduous journey and can never be sure that they will find it.
Judges, however wise or eminen...
Innovations are occurring at a bewildering rate: as many now arrive in a year as once arrived in a millennium.选自《Old Father Time Becomes a Terror》—Richard Tomkins译文：新技术纷至沓来，令人目不暇接：一年涌现的技术创新相当于以前一千年。请问老师这句...
Putin says Russia to target U.S. if missiles put in Europe.
老师说新闻标题省略Russia后省略了is,missiles后边省略了were如果是虚拟语气的话那么第一段President Vladimir Putin signaled Russia will aim new weapons at the U.S. if it stations missiles in Europe after quitting...