关于胰液的描述,错误的是
B
暂无解析
EachyearintheUnitedStates,manyblackteenagers_______ofschool,eitherbecausetheycannotkeepuportheyhavetoworktosupporttheirfamily.
heteachertoldthemsincelight________(travel)fasterthansound,lightning________(appear)togobeforethunder.
________they'vegottoknoweachotheralittlebetter,theygetalongjustfine.