Plans have been proposed ______ the largest dam in the world to be built along the Congo river.
We have to ______ everything question in detail ______ we take action.
It is clear that no use can be made ______radium _____we don’t know clearly the characteristics of it.
From my point of view, the theory that ______ by the scientist is not quite scientific.
The invention of steam engine greatly sped up the industrial revolution, which _____ a lot to the take-off of the world.
I came here with your mother ________ to see you.