某跨越一条650m宽河面的高速公路桥梁，设计方案中其主跨为145m的系杆拱桥，边跨为30m的简支梁桥。试问，该桥梁结构的设计安全等级，应如下列何项所示（）？

A.一级 

B.二级 

C.三级 

D.由业主确定

根据句意及汉语提示，写出各单词的正确形式。

小题1:We’ll have to ______（训练）before the next match.

小题2:Our teachers often ______ (鼓励)students to ask questions in class.

小题3:The girl ______ (尖叫) when she saw the snake.

小题4:The old man is very sick. He takes a lot of ______ (药) every day.

小题5:______ (令人伤心地), many people still don’t want to take any actions to protect the animals.

小题6:It is really ______ (幸运的) for me to pass the driving exam .

小题7: Millie didn’t clean the room last week, she visited her friends ______ (代替).