单选题：Training astronauts _________ not an easy thing.

题目分类：英语三级A级
题目类型：单选题
查看权限：VIP

题目内容：

Training astronauts _________ not an easy thing. A． are
B． is
C． were
D． be

参考答案：

答案解析：

The heart is an important organ of circulation _________ fun

The heart is an important organ of circulation _________ function is to pump blo

分类：英语三级A级题型：单选题

The (long) ________ of the river is 3,000 miles.

The (long) ________ of the river is 3,000 miles.

分类：英语三级A级题型：单选题

Ocean transportation is widely used because it is a relative

Ocean transportation is widely used because it is a relatively low-cost way to t

分类：英语三级A级题型：单选题

（　　）中央处理器（　　）软磁盘

（　　）中央处理器（　　）软磁盘

分类：英语三级A级题型：单选题

Which of the following novels was written by Emily Bront67

Which of the following novels was written by Emily Bront67A．0fiver Twis B．Middle

分类：英语三级A级题型：单选题