* * 流血由少渐多，腹痛加重，宫口逐渐开大，有组织物堵塞于宫口：
A．不完全流产B．稽留流产C．难免流产D．先兆流产E．完全流产
参考答案：C
Robert is away. He _______ America since last week.
A．has been to
B．has joined a club in
C．has studied in
D．has become a manager in
数据库的实施主要包括以下四项工作：用DDL定义数据库结构，数据装载，编写与调试应用程序以及______。
