某探究小组用洗净的废铜屑制备硝酸铜，下列方案中既节约原料又环保的是（ ） A．C

抛物线y=ax²+bx（a＞0，b＞0）的图象经过第（    ）象限。

根据第一个句子的意思，完成第二个句子，每个空格只准填一个单词。

1. The newspaper says the price of houses will continue to rise.

    It _______ _______ that the price of houses will continue to _______ _______.

2. We don't have to leave so early.

    There is _______ _______ _______ _______ to leave so early.

3. I visited a specific house last Sunday. I will remember it forever.

    I will _______ remember the specific house _______ _______ _______ last Sunday.

4. His Chinese has improved a lot since he came to China.

    He has _______ great _______ in Chinese since he came to China.

5. I expect to go to your party.

    I am _______ _______ _______ _______ to your party.

消化性溃疡X线检查最具诊断意义的是（）

A.辐射状黏膜

B.痉挛性切迹

C.球部激惹

D.局部压痛

E.龛影

顶飞机时，注意：

A、左右油箱的油量必须平衡。

B、所有的门必须关好。

C、飞机上不得有人。

D、ABC都对。