Without facts, we cannot form a worthwhile opinion for we need to have a factual knowledge ________ our thinking.
| A．which to base on | B．which to be based on |
| C．on which to be based | D．on which to base |
【2015·陕西】Reading her biography, I was lost in admiration for ________Doris Lessing had achieved in literature.
| A．what | B．that | C．why | D．how |
【2015·四川】The exhibition tells us____we should do something to stop air pollution.
| A．where | B．why | C．what | D．which |
【2015·重庆】We must find out ____ Karl is coming, so we can book a room for him.
| A．when | B．how | C．where | D．why |
【2015·浙江】If you swim in a river or lake, be sure to investigate ____ is below the water surface.Often there are rocks or branched hidden in the water.
| A．what | B．who | C．that | D．whoever |
A ship in harbor is safe, but that's not ______ ships are built for.
| A． | what | B． | whom | C． | why | D． | when |