It is often said that eyes can speak. Do you have such kind of (经历)? On a bus you may look at a (陌生人), but not too long. If he (注意到) that he is looked at, he may feel (不舒服的). It is the same in daily life. When you are looked at for several more (次数), you will look at yourself up and down in order to see if there is something wrong with you. If nothing goes wrong, you will feel (生气的) with the person who is looking at you. Eyes can speak, right?
Looking too long at someone may seem to be (不礼貌的). But sometimes things are different. If you wish to draw someone's attention, you may look at him or her for more than ten (秒). For lovers, they enjoy looking at each other longer to show the love that words cannot (表达) clearly. Eye communication should be done according to the (关系) between the two people and the certain situation.