男性,55岁,进行性吞咽困难三个月,体重下降5kg,查体无阳性所见。
首选检查方式是
A.胸部CT
B.食管超声波检查
C.食管拉网
D.食管镜检查活检
参考答案:D
单句改错(每句均有一处错误)。
( ) 1. The boy fell from the bike yesterday.
( ) 2. Let's go cross the street together.
( ) 3. My sister watched TV at seven yesterday evening.
( ) 4. The boy got up lately this morning.
( ) 5. In the fact I know nothing about the accident.
离心泵在工作中不可能发生“气穴现象”的原因是()。
A、吸入管阻力过大
B、液温过高
C、吸入管漏出液面
D、吸入液面压力降低