题目

图中减数分裂过程某阶段的描述，正确的是( ) A．同源染色体移向两极 B．非姐妹染色单体交换结束 C．减数第二次分裂的中期 D．姐妹染色单体排列在赤道板上 答案：B题图为动物细胞减数第一次分裂中期图，同源染色体两两整齐地排列在赤道板上，其中非姐妹染色单体的互换在前期已经结束。  完形填空阅读下面短文，掌握其大意，从短文后各题所给的四个选项（A、B、、C、D)中，选出可以填入空白处的最佳选项。After a long day at school，I walked home with my heavy schoolbag．Sleepy and________，I threw my things on the couch and grabbed something from the________to eat．I passed by the living room and wished I could watch TV，but I knew my ________ would take me the whole night．I took my schoolbag and went ________to my room．I tried to understand chemistry and ________sleepiness at the same time．I tried to keep my eyes ________and I wanted something to cheer me up．Later, I________the sound of the front door opening．And I waited for it—the sound of my mom singing. Though she sang off-key(跑调)，________ made me excited that she was here．I ran down to________my mom．We hugged each other and talked for a while．I like it when my mom was happy．Her________seemed to flow down to me and I got the strength to________the stress again．Sometimes, I wonder how my mom can still be ________after coming back from work．Every weekday，she wakes up________in the morning to go to work and spends all hour on the bus before getting downtown．At a ________factory，she works standing for the whole day and draws patterns for clothes over and over．After work，my mom at times gets stuck in________ for two hours on her way back home．When I________my school life with her work life, I should not be the one to________．At least I have some interesting things to do at school, but one mistake at work can cost my mom her job．I ________that my mom has a positive attitude and lives her life with a joyous heart，which encourages me to do my work well, ________there may be difficulties．Seeing her happy makes me feel________，too．1.A. heavy B. busy C. hungry D. unlucky2.A. classroom B. kitchen C. bedroom D. apartment3.A. dream B. supper C. homework D. experience4.A. downstairs B. outside C. upstairs D. inside5.A. break off B. put off C. get off D. fight off6.A. opening B. opened C. open D. closing7.A. felt B. listened C. raised D. heard8.A. which B. that C. it D. but9.A. Look B. greet C. said to D. help10.A. need B. idea C. faith D. energy11.A. face B. change C. accept D. 1eave12.A. creative B. sensitive C. competitive D. positive13.A. early B. soon C. fast D. 1ate14.A. furniture B. shoe C. car D. clothing15.A. chat B. traffic C. duty D. task16.A. replace B. exchange C. connect D. compare17.A. complain B. decide C. study D. play18.A. achieve B. notice C. appreciate D. improve19.A. however B. though C. despite D. at least20.A. good B. skillful C. successful D. important