Bài tập củng cố

https://imgix3.ruangguru.com/assets/miscellaneous/08esl12inf_unit201220life20on20other20planets_01.png_ep9ivl_12611.png_v6imkn_5536.png|https://imgix3.ruangguru.com/assets/miscellaneous/08esl12inf_unit201220life20on20other20planets_02.png_uobchh_75371.png_5gggon_8058.png|https://imgix3.ruangguru.com/assets/miscellaneous/08esl12inf_unit201220life20on20other20planets_03.png_nobfgr_37971.png_dqsvmn_4188.png|https://imgix3.ruangguru.com/assets/miscellaneous/08esl12inf_unit201220life20on20other20planets_04.png_9hewvj_77511.png_yxscep_1887.png