附睾尾部实质性肿大，表面不光滑，结节状，质地硬韧，界限不清者，为（）
A.子痰
B.子痈
C.肾岩
D.附睾恶性肿瘤
E.附睾良性肿瘤
参考答案：D
The companies are working together to create _____ they hope will be the best means of transport in the
21st century. [ ]
A. which
B. that
C. what
D. who
阴极的金属表面连续地向外发射出电子的现象，称为（）。
