secure vt.①使安全，保卫②获得 adj.安全的，确定无疑的
We secured all of the doors of the lab before leaving.在离开之前，我们把实验室的所有门都关好了。
Secure your tickets early.早点把票弄到手。
We know in advance that our victory is secure.我们提前就知道我们必胜无疑。
semester n.学期
Many students arrange internships or work-study placements during the second semester.许多学生在第二学期安排实习或申请勤工俭学。
senate n.议会；参议院，上院
The law has no chance of being passed by the Senate.这部法律毫无机会被议会通过。
senior adj.年长的；资格较老的；地位较高的
Some senior members of the staff have worked here for more man 20 years.有些资深的员T已经在这里工作了20多年了。
sensible adj.明智的，合理的；可感觉到的，明显的
His sensible decision greatly promoted our enterprise.他明智的决定极大地促进了我们公司的发展。
A sensible trend is that people are using computers more.一个非常明显得趋势是，人们越来越多地使用计算机。
sensitive ①灵敏的②敏感的，易受影响的
Dogs are more sensitive to odors than people are.狗比人对气味更敏感。
Bob is too sensitive about what people think about him.鲍勃过于在意人们对他的看法。
sequence n.序列,顺序
Arrange the names in alphabetical sequence.按字母顺序排列姓名。
series n.连续；系列
A series of rainy days spoiled their vacation.连续的雨天让他们的假期泡汤了。
serious adj. ①严肃的,认真的②严重的
Are you joking or are you serious？你是开玩笑呢，还是认真的？
lt's a serious illness—you can die of it.这是一种严重的疾病----你可能会因此而丧生。
session n.①会议②一段时间；一次
The UN Security Council held an emergency session to discuss the crisis.联合国安理会召开了紧急会议来讨论此次危机。
There'll be a question-and-answer session at the end of this morning's lecture.今天上午的演讲结束后，将有一个问答环节。