后牙鸠尾峡的宽度一般为颊舌牙尖间距的()。
A.1/4到1/3
B.1/3到1/2
C.1/5到1/4
D.1/2到2/3
E.2/3到3/4
参考答案:B
女,28岁,颈部逐渐变粗,甲状腺肿大,呼吸困难,吞咽困难。该患者可能是()
A.缺锰
B.缺锌
C.缺碘
D.缺硒
E.缺铁
Millions of trees _____ around our city every year. Our environment is getting better.[ ]
A. are planting
B. were planted
C. planted
D. are planted