1 . 如果放任不管，在他们成年后这些习惯会导致更严重的有害习惯。（状语从句的省略）
These bad habits, ___________, ____________, could lead to more serious ones when they become adults.

2 . If __________ into a warm room, a piece of ice will turn into water soon.

A．take

B．took

C．taken

D．to be taken

3 . I had never imagined________ so many people in Nanjing Avenue on that day.

A．that there to be	B．there being
C．there to be	D．that there being