be 动词后,一般不用动词原形,do后面才是动词原形 be动词后,用动词ing,表示现在进行时,或用be动词+过去分词表示被动语态。
be：
v.是;有;存在;位于;在(某处);(在某时或某地)发生。
aux.与过去分词连用构成被动语态;与现在分词连用构成进行时;用于反意疑问句。
A free trade agreement would be advantageous to both countries.
自由贸易协定对两国都会有利。
She was not only intelligent but also very musical.
她不仅聪明，而且极具音乐天分。
The first part of the plan has been safely accomplished.
计划的第一部分已顺利完成。
Patience is one of the most important attributes in a teacher.
耐心是教师最重要的品质之一。
A single red LED shows that the power is switched on.
单支红色发光二极管表示电源已接通。
温馨提示：
