To navigate to the declaration of a class, method or variable used somewhere in the code, position the caret at the usage and press Ctrl+B. You can also click the mouse on usages with the Ctrl key pressed to jump to declarations.请教一下，usage前面为什么一下用at，一下用on？
Certainly, some felt that
the time had come to find out once and for all the alphabetic powers of the Chinese script, if any were hidden in its
folds.这里的alphabetic power和folds如何更为准确地理解和翻译呢？
这里的背景是介绍旅游时可以去什么地方，然后一一列举这些地方：time share apartment: accommodation which one owns, say, a 26th part of
and so has the right to stay there
for 2 weeks every year.这里and so是什么用法，后面has为什么没有主语？
...;malign activity was recently made available when the State Department published its annual report on global terrorism.近日，伊朗从事邪恶活动的证据公之于众，美国国务院发布了关于全球恐怖...
...t turn two pages at once and make sure you find the repeats
in the music when you have to go back to the right spot.” Mr Titterton
explained.本段材料摘自2021年“新高考”英语全国卷I的阅读理解B。我对其中的 at once 不理解，因翻译不通。
读小说时读到Three days later, when he was alone with 某人 and I could follow the course of their conversation from my room, I discovered that he can be very different, relaxed and high-spirited. I talked to him myself afterwards. A perfect gentleman, exceptionally urbane. 我查了一下hig...
...、这两句话是不是一样的结构，但是第一句but后面跟的是从句，所以要加that呢？that后是不是一个名词性从句呢？B、 第一句如果but后面是名词，是不是就不用that了？如：What makes his parents worry is not his grades but his health.