__________，many people go in for them and benefit from them.
| A．However some sports are challenging |
| B．However challenging some sports are |
| C．No matter how challenging are some sports |
| D．No matter how some sports are challenging |
The doctor thought __________ would be good for you to have a holiday.
| A．this | B．that |
| C．one | D．it |
The boy entered the room quietly in order to avoid __________ his parents.
| A．being waken up | B．to wake up |
| C．waking up | D．to have waken up |
Taking weight-loss pills will __________ our health.
| A．effect | B．affect |
| C．error | D．effort |
Does it ever __________ to you that they would be punished for being late?
| A．strike | B．occur |
| C．happen | D．appear |
The president, together with his bodyguard，__________ to the nuclear station __________ there was an accident 20 minutes ago.
| A．have come; which | B．came; in which |
| C．has come; where | D．came; in which |