对于可逆反应mA(g)+nB(g)
pC(g)+gD(g),若其它条件都不变,只是在反应前是否加入催化剂,可得到两种v-t图象如图所示,如下关系正确的为( )
①a1=a2 ②a1<a2 ③b1=b2 ④b1<b2 ⑤t1>t2 ⑥t1=t2 ⑦两图中阴影部分面积相等 ⑧后图阴影部分面积更大
| A.②④⑤⑦ | B.②④⑥⑧ | C.②③⑤⑦ | D.②③⑥⑤ |
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 |
I can’t leave. She told me that I ______ stay here until she comes back.
| A.can | B.must | C.will | D.may |
—— Do you mind my opening the window? It’s a bit hot in here.
—— ______ , as a matter of fact
| A.Go ahead | B.Yes, my pleasure![]() |
C.Yes, I do | D.Come on |
It’s high time you had your hair cut ; it’s getting _______ . 
| A.too much long | B.much too long ![]() |
C.long too much | D.too long much |