________ repeatedly, the problem still appeared in the beginners’ homework.
| A．Explaining | B．Having explained |
| C．Having been explained | D．To be explained |
They only stood there with their arms ______ in front of their chest rather than give us a hand.
| A．folding | B．folded | C．to be folded | D．being folded |
With their son ______, the old couple lived a hard life.
| A．disappointing | B．disappointed | C．to be disappointed | D．being disappointed |
He must have been working really hard these days. This morning, I even noticed ______ behind his ears.
| A．grey hair | B．grey hairs | C．the grey hair | D．much grey hair |
On almost all the buses in our city, there are seats ______ reserved for disabled and elderly passengers.
| A．particularly | B．in particular | C．especially | D．specially |
We’d better hurry up. The exhibition hall is a bit far from ______ we are now.
| A．what | B．which | C．that | D．where |