风湿性二尖瓣狭窄的典型杂音是(),二尖瓣狭窄典型的症状是()。
参考答案:心尖可闻第一心音亢进和舒张中期隆隆样杂音;劳力性呼吸困难
The little girl was crying because her mother didn’t allow her _______ the ice-cream.
A.eat
B.eats
C.to eat
D.ate
TnA家庭的转座子通常转移三种基因:转座酶、解离酶和氨苄抗性基因。