A:合上开关K电路稳定时,A2始终比A1亮
B:合上开关K接通电路时,A2和A1都逐渐变亮
C:断开开关K切断电路时,A2先熄灭,A1过一会儿才熄灭
D:断开开关K切断电路时,A1和A2都要过一会儿才熄灭
动词填空 用括号内所给动词的适当形式填空,并将答案写在答题卡标有题号的横线上。⑴It's said that the new film directed by Feng Xiaogang ____ (film) in two months.⑵Why didn't David come to my birthday party yesterday? He ____ (go) to Beijing.⑶The novel she devoted most of her lifetime to ____ (come) out last month.⑷When I got home, I was surprised to find my son ____ (prepare) for tomorrow's test.⑸It's reported that this kind of fashionable bag ____ (carry) easily.⑹Oh, my god! Little Tom seems to be sad. I guess something ____ (happen) to him.⑺Would you please not ask any more? I'd rather____ (not tell) you about it.⑻What happened to you? I nearly hit a person on my way home last night. I could hardly see the road clearly because it____ (rain) so heavily.
①若{an}是“等方差数列”,则数列{an2}是等差数列;
②{(﹣1)n}是“等方差数列”;
③若{an}是“等方差数列”,则数列{akn}(k∈N*,k为常数)不可能还是“等方差数列”;
④若{an}既是“等方差数列”,又是等差数列,则该数列是常数列.
其中正确的结论是____.(写出所有正确结论的编号)
以党的十一届三中全会为标志,我国实现了伟大的历史转折,进入社会主义事业发展的新时期。
材料一:大包干,大包干,直来直去不拐弯。保证国家的,留足集体的,剩下自己的。
材料二:深圳的发展和经验证明,我们建立经济特区的政策是正确的。
——邓小平
目前我国城市环境污染主要包括( )