My hometown has changed so much that I can't ________ it.
Most experts agree that human activities such as the clearing of large areas of forests, and farming on a large scale _________ the problem of global warming.
With the help of the collected money, subways can be built sooner and better, _______ brings convenience to citizens.
We spent hours driving and another few hours waiting, only _________ that the plane would be delayed until midnight.
In the experiment we kept _____ watchful eye on ______ developments and recorded every detail.
I remember the time _____ Eric won that speech competition.A where B why C when D which