People begin to understand the natural resources are not （) , which can be used up wi

According to the author, at what age does a child probably begin to learn about sets and n

According to the author, when does culture begin to emerge？A．When people decide what and h

Why did employers begin to offer jobs opportunities to the disabled？A．Because people becam

A（n) ______lack of food brought hunger to the Iraqi people.A．crucialB．criticalC．urgentD．ac

People did not begin to use unmanned vehicles in undersea exploration until recently becau

That the letter is found and answered so many years later is a（n)______to all the people.