A) must have been C) should have been B) needed to be D) ought to be
44. It is believed that milk _____ something that will promote the health of human beings.
A) contains B) includes
C) involves
D) compromises
45. Scientists have _____ a solution for water pollution.
A) come up with C) done away with B) fit in well with D) shared for 46. _____ than he was called out again.