金银花有效活性成分为绿原酸,又名咖啡鞣酸,具有广泛的杀菌消炎功效,结构如下图所示,下列有关绿原酸的说法正确的是
A.绿原酸的分子式为C16H12O9 |
B.绿原酸能和NaHCO3溶液发生反应放出CO2气体 |
C.1mol绿原酸最多与8 molNaOH反应 |
D.绿原酸分子中有4种化学环境不同的氢原子 |
Jenny nearly missed the flight______ doing too much shopping.
A.as a result of | B.on top of | C.in front of | D.in need of |
The CDs are on sale! Buy one and you get ______ completely free.
A.other | B.others | C.one | D.ones ks |
Progress______ so far very good and we are sure that the work will be finished on time.
A.was | B.had been | C.has been | D.will be |
Charles was alone at home, with_______ looking after him.
A.someone | B.anyone | C.not one | D.no one |
It is often ______ that human beings are naturally equipped to speak.
A.said | B.to say | C.saying | D.being said |