1.——Where is our maths teacher?
——She is in the classroom,( ) the exercises ( ) the students have done at home.
A.explaining;/ B.explaining;for C.explained;to D.explained;from
2.Yesterday a street—beggar bought a lottery ticket purposelessly,( ) him a millionaire overnight.
A.making B.makes C.to make D.made
为什么第一题不选C,第二题不选A?