nobody knew what would happen the ______(follow)day 1.she is

nobody knew what would happen the ______(follow)day 1.she is very clever,she can work out the math
1.she is very clever,she can work out the maths problem_____(easy)
2.this book is ____(help)to us students
3.the girls started(dancing ) half an hour ago(对括号内提问)
___ ____the girls ____ ____ half an hour ago?