If you want to study the nature of the universe, first of all, you must be clear about its ________.
The government is aiming to reduce the unemployment, but it’s quite _______ to have a job at all these days.
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.