在平面直角坐标系中,已知直线过点P(-2,1)和点Q(1,4),则直线PQ的斜率

题型:选择题

问题:

在平面直角坐标系中,已知直线过点P(-2,1)和点Q(1,4),则直线PQ的斜率是(  )

A.1

B.-3

C.3

D.2

考点:直线的倾斜角与斜率
题型:选择题

Throughout history,the language________by a powerful group spreads across a civilization.

A.speaking

B.spoken

C.to speak

D.to be spoken

题型:选择题

常我们把地形分为()两大类。

A、地物和地貌

B、丘陵和河流

C、丘陵和平原

D、河流和平原

题型:选择题

招标人和中标人应当自中标通知书发出之日起()内,按照招标文件和中标人的投标文件订立书面合同。招标人和中标人不得再行订立背离合同实质性内容的其他协议。

A.十五日

B.二十日

C.二十五日

D.三十日

题型:选择题

Drug use is rising dramatically among the nation’ s youth after a decade of decline. From 1993 to 1994, marijuana use among young people (1) from 12 to 17 jumped 50 percent. One in five high school seniors (2) marijuana daily. Monitoring the Future, which (3) student drug use annually, reports that negative attitudes about drugs have declined for the fourth year in a row. (4) young people see great risk in using drugs. Mood-altering pharmaceutical drugs are (5) new popularity among young people. Ritalin, (6) as a diet pill in the 1970s and now used to (7) hyperactive children, has become a (8) drug on college campuses. A central nervous system (9) , Ritalin can cause strokes, hypertension, and seizures. Rohypnol, produced in Europe as a (10) tranquilizer, lowers inhibitions and suppresses short-term memory, which has led to some women being raped by men they are going out with. (11) taken with alcohol, its effects are greatly (12) . Rock singer Kurt Cobain collapsed from an (13) of Rohypnol and champagne a month before he committed (14) in 1994. In Florida and Texas, Rohypnol has become widely abused among teens, who see the drug as a less expensive (15) for marijuana and LSD. Alcohol and tobacco use is increasing among teenagers, (16) younger adolescents. Each year, more than one million teens become regular smokers, (17) they cannot legally purchase tobacco. By 12th grade, one in three students smokes. In 1995, one in five 14-year-olds reported smoking regularly, a 33 percent jump (18) 1991. Drinking among 14-year-olds climbed 50 percent from 1992 to 1994,and all teens reported substantial increases in (19) drinking. In 1995, one in five 10th graders reported having been drunk in the past 30 days. Two-thirds of high school seniors say they know a (20) with a drinking problem.

12()

A.enlarged

B.confirmed

C.exaggerated

D.magnified

题型:选择题

拜耳法的基本原理()

A、用NaOH溶液溶出铝土矿,所得到的铝酸钠溶液在添加晶种、不断搅拌的条件下,溶液中的氢氧化铝便呈氧化铝析出

B、分解得到的母液,经蒸发浓缩后在高温下可用来溶出新的铝土矿

C、用NaOH溶液溶出铝土矿,所得到的铝酸钠溶液在添加晶种、不断搅拌的条件下,溶液中的氧化铝便呈氢氧化铝析出

D、分解得到的母液,经蒸发浓缩后在低温下可用来溶出新的铝土矿

更多题库