Cho hai tập  A = x ∈ R x + 3 < 4 + 2 x  và  B = x ∈ R 5 x − 3 < 4 x − 1  

Tất cả các số tự nhiên thuộc cả hai tập A và B là:

A. 0;1;2

B. 0 và 1

C. 1

D. 0

4000 vòng

Not until Kentucky’s Mammoth Cave had been completely explored in 1972 _________.

A. when was its full extent realized

B. the realization of its full extent

C. was its full extent realized

D. that its full extent was realized