Mr. Smith didn’t understand _____ made his son so upset that evening.
| A．what was it | B．why it was this | C．how that was | D．what it was that |
Tom does speak Chinese well, but his reading and writing skills leave much _________.
| A．to improve | B．to be improved | C．being improved | D．having improved |
It remains unknown _____the peace talk between the two countries is going to lead.
| A．why | B．when | C．how | D．where |
Every weekend, there is a meeting and our head teacher, with five of us, ____ it.
| A．attends | B．to attend | C．attend | D．attending |
– Is everybody here?
– Not yet… Look, there ____ the rest of our visitors!
| A．comes | B．is coming | C．come | D．are coming |
Everyone, please remain ____ until the plane has come to a complete stop.
| A．seat | B．seated | C．seating | D．to seat |