It is along the Mississippi River ____ Mark Twain spent much of his childhood.
A.how B.which C.that D.where
____ a certain doubt among the people as to the practial value of project.
A.It has B.They have C.It remains D.They remains
It _____ John and Mike who cleaned the room.
A.are B.were C.was D.has been
Will you mend the cleaner yourself ,______ shall we ask someone else to fix it
A.and B.so C.or D.for
答案CDCC
需要解釋原因