【单选题】假设你想证明:每一个可以写成k(k+1)(k+2)的整数乘积都能被6整除。如果你想用分情形证明法来证明它,那么你应该用下面哪一个集合?
B.
当k被3除,余数为0;当k被3除,余数为1;当k被3除,余数为2;
【单选题】Before taking out the ( ),give the engine at least one complete turn.
【简答题】Turn-taking is a characteristicof ____________.
【判断题】People are bound by the rules of turn-taking in conversation.
【单选题】— How is your sister? — She _______ quite good after the operation, but she is taking a turn for the worse today.
【单选题】The central government is taking measures to the prices of daily necessities.
【单选题】--- Do you know the reason _________ pilots turn off the plane’s lights before taking off? ---The practice is for the passengers to adjust to the dark _________ an emergency.
【判断题】I think our fortune is taking a turn for the better.
【单选题】[Based on Figure 6-17] How is the burden of the tax shared between buyers and sellers? Buyers bear
A.
three-fourths of the burden, and sellers bear one-fourth of the burden.
B.
two-thirds of the burden, and sellers bear one-third of the burden.
C.
one-half of the burden, and sellers bear one-half of the burden.
D.
one-fourth of the burden, and sellers bear three-fourths of the burden.