D.not making any breakthrough in her field

       49.What can be inferred from the last paragraph?

       A.The mother is successful in her career.

       B.The family members like travelling.

       C.The author had little time to play when young.

       D.The marks on the breadboard have disappeared.

       50.In the author’s mind, her mother is             .

       A.strange in behaviour

       B.keen on her research

       C.fond of collecting old things

       D.careless about her appearance