Our English ______ far better in a month if we try harder.

A．becomes

B．will become

C．has become

D．became

关于恒前牙和乳前牙的牙冠宽度差异量补偿方法，下列说法错误的是

A．乳牙间有适当的牙间隙

B．恒切牙萌出时更偏向唇侧

C．乳牙恒牙的大小比例不协调

D．前磨牙萌出时较乳牙偏向颊侧，增加了牙弓宽度