阅读下面短文，从短文后所给各题的四个选项(A、B、C和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．By the time I got home, I was sweaty, 　　1　　 and hungry．I threw my things on the couch and grabbed something from the kitchen to 　　2　　．I passed by the living room and wished I could watch TV, but I knew my 　　3　　　would take me the whole night．I grabbed my schoolbag and went 　　4　　 to my room, feeling defeated．I tried to understand chemistry and 　　5　　 sleepiness at the same time．I was stressed out and 　　6　　．I wanted something to cheer me up．

　　Later in the evening, I 　　7　　 the sound of the front door opening．And I waited for it－the sound of my mom singing．　　8　　 she sings off－key(跑调), it made me excited that she was here．I ran down the stairs to greet my mom．We 　　9　　 and I ran back upstairs to do homework again．I like it when my mom was happy．Her 　　10　　 flowed down to me and I got the strength to 　　11　　 the stress again．

　　Sometimes, I wonder how my mom can still be 　　12　　 after coming back from work．Every weekday, she wakes up 　　13　　 in the morning to go to work and spends an hour on the bus before getting downtown．At a 　　14　　 factory, she works standing for the whole day and draws patterns for clothes over and over．After work, she gets stuck in 　　15　　 for two hours on her way back home．When I 　　16　　 my school life with her work life, I should not be the one to 　　17　　．At least I have some fun things to do at school, while one mistake at work can cost my mom her job．I 　　18　　　that my mom has a positive attitude and lives her life with a joyous heart even though there may be 　　19　　 ．Seeing her happy makes me feel 　　20　　, too．