【判断题】因 锅炉产生的蒸汽压力较大,故开汽时应控制汽量,应徐徐放汽。
【判断题】遗忘的进程并不均衡,而是先慢后快,遗忘的速度随时间的延长而愈来愈快。
【判断题】记忆的研究表明,遗忘进程先快后慢,遗忘的速度是均衡的。
【单选题】下列有关命题的说法正确的是 [ ]
A.
命题“若x 2 =1,则x=1”的否命题为:“若x 2 =1,则x≠1”
B.
命题“若x=y,则sinx=siny”的逆否命题为真命题
C.
命题“存在x∈R,使得x 2 +x+1<0”的否定是:“对任意x∈R,均有x 2 +x+1<0 ”
【单选题】Which of the following is NOT MENTIONED in the third paragraph?
A.
Group work gives pupils the opportunity to learn to work together with others.
B.
Pupils also learn to develop their reasoning abilities
C.
Group work provides pupils with the opportunity to learn to be capable organizers.
D.
Pupils also learn how to participate in teaching activities.
【单选题】下列有关命题的说法正确的是( )
A.
命题“若x=y,则sinx=siny”的逆否命题为真命题
B.
函数y=tanx的定义域{x|x≠kπ,k∈Z}
C.
命题?x∈R使得x 2 +x+1<0”的否定是:?x∈R,均有x 2 +x+1<0”
D.
a=2”是“直线y=-ax+2与y= a 4 x-1 垂直”的必要不充分条件
【判断题】遗忘进程先快后慢,遗忘的速度是均衡的。( )