Excuse me, I get back my umbrella, madam? –I’m really sorry. I thought it was mine.

Isoxygentheonlygas______helpsfireburn? [ ]

I cannot______ puzzled，for I simply cannot understand how I could have made such a stupid mistake.

Mum, why not having hamburgers instead of dumplings? —-Good idea.

Aunt Tina will visit us soon. _______ is arriving tomorrow morning.