下列哪种情况，严禁采用放顶煤开采（）。A.煤层平均厚度小于4m的 B.采放比大于1

短文填词。

     There are 12 (1)m            in a year. In different months, we have different (2)e           . Our school's

birthday is (3)S            1. It's the (4)n             month of the year. So we have School Day in that month.

There are (5)C            (圣诞节) and New Year's Day in December. So we have Art (6)F            in the

month. And we also have (7)M            Party. At the party we can listen to our (8)f            songs.

(9)W            is our school trip? It's in March or (10)A           . It's spring. It's warm.

患者男性，48岁，因吞咽梗噎感半年来院就诊，目前仅能进半流质食物。查体：稍消瘦，锁骨上未扪及肿大淋巴结。食管吞钡X线片示食管中下段4CM长之局限性管壁僵硬，黏膜部分中断，钡剂尚能通过。

首先考虑的诊断是（）。

A.贲门失弛缓症

B.食管炎

C.食管良性肿瘤

D.食管癌

E.食管憩室

自然主义文学的发源地是（）。

A．英国

B．俄国

C．德国

D．法国

类毒素是由（）制成的。

A.肉毒素

B.外毒素

C.病毒