输入受限的双端队列是指元素只能从队列的一端输入，但可以从队列_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题单项选择题

输入受限的双端队列是指元素只能从队列的一端输入，但可以从队列的两端输出，如图1-5所示。若有8，1，4，2依次进入输入受限的双端队列，则得不到输出序列（）

A．2，8，1，4

B．1，4，8，2

C．4，2，1，8

D．2，1，4，8

答案

参考答案：D

完形填空

完形填空
From Monday 1 Friday, American students usually get up at seven. Then they wash their faces and 2 . They usually have eggs, bread, fruit and a glass of milk. After breakfast, they 3 on footor by school bus. Some students ride bikes to school. They get to school 4 eightthirty. Then they put their backpacks in their lockers and 5 . Only one book, a table and a pencil to each class. In middle school, students have classes for six 6 . Their classes are usually English writing, math, history, 7 , P. E. and art. 8 students have lunch at school. They usually have meat, vegetables, fruit, bread and drink. 9 most students like pizza, hot dogs and hamburgers better. Students 10 have a short sleep. They go back to have classes after lunch until three o'clock. Then they 11 . Students usually play 12 sports or watch TV before dinner. They have dn er at six 13 . They usually have soup, meat, vegetables, rice or pasta. 14 they do their homework with their parents. Sometimes they play or talk with their parents. On Saturday they often go shopping, 15 their grandparents or go to a park with their parents. And on Sunday they go with their parents to church in the morning and have a big dinner at one o'clock in the afternoon.
( )1. A. on ( )2. A. have dinner ( )3. A. go to school ( )4. A. at ( )5. A. take ( )6. A. hours ( )7. A. music ( )8. A. At noon ( )9. A. And ( )10.A. aren't ( )11.A. go to home ( )12.A. a ( )13.A. in the evening ( )14.A. After dinner ( )15.A. see	B. in B. have breakfast B. get to school B. in B. bring B. days B. sport B. In the evening B. So B. doesn't B. goes home B. an B. in the morning B. After the dinner B. look at	C. to C. have lunch C. goes to school C. on C. buy C. weeks C. pants C. In the afternoon C. For C. isn't C. go home C. the C. at night C. Before dinner C. watch	D. at D. take a shower D. go school D. for D. read D. months D. rulers D. In the morning D. But D. don't D. goes to home D. / D. in the aftemoon D. Before the dirner D. look

单项选择题

我国的公务签证一般不发给下列外国人（）。

A、持公务护照的外国人

B、外国身份较高的知名人士

C、持官员护照的外国人

D、持特别护照的外国人