is出现是什么时态

　　Much of the form was not applicable to me.

　　表格中很多部分不适用于我。

　　She was not only intelligent but also very musical.

　　她不仅聪明，而且极具音乐天分。

　　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。

　　This drug is known to have adverse side effects.

　　众所周知，这种药具有不良副作用。

　　It is important that students develop an awareness of how the Internet can be used.

　　重要的是学生逐渐懂得如何使用互联网。