羊水来源,在妊娠中期时,()是羊水的重要来源。
参考答案:胎儿尿液
______协议可支持在电子邮件中的包含文本、图像、声音、视频及其应用程序的特定数据。
A.HTTP B.SMTP C.FTP D.MIME
I _____ a new book,but my brother ______ one. [ ]
A. don't have ; have
B. doesn't have ; has
C. have ; doesn't have
D. have ; has