题目：Until recently, body heat has caused problems because it _______.
A、was difficult to collect
B、 came in a variety of forms
C、was difficult to get rid of
D、tended to be absorbed by physical objects
题目：Until recently, body heat has caused problems because it _______.
A、was difficult to collect
B、 came in a variety of forms
C、was difficult to get rid of
D、tended to be absorbed by physical objects
