This river is so big that it is impossible to build a _______under it without modern technology.
B
暂无解析
IntheUnitedStates,theforeignpolicyisdecidedbythe________government,notbyeachstate.
Itisnot---_______formetoreturnallthebookstothelibrarynowbecauseIstillneedsomeofthemformyresearch.
Studentswith_______problemsmayapplyforstudentloans.