单项选择题
Gravity is sure to play an important part, （）the ball （）into the air won’t go up.
A．as, thrown B．for, thrown C．since, throwing D．as, throwing
单项选择题 An investigation was made into the accident, （）five people were killed.
单项选择题 Long before children are able to speak a language, （）communicate through facial expressions and by making noises.
