根据达芬奇的研究，人的视觉不仅仅与眼睛有关。

已知数列{a_n}是等差数列，a₂=8，a₈=26，从{a_n}中依次取出第3项，第9项，第27项，…，第3ⁿ项，按原来的顺序构成一个新数列{b_n}，则b_n=______．

Since the office building is being repaired and painted, we will have ______ offices in the hotel．

A．temporary

B．contemporary

C．professional

D．permanent

The study surveyed 500 families and found the main   problem people suffered was tiredness, followed by loneliness and anxiety.

A．domestic

B．public

C．psychological

D．biological

数控系统录入方式（MDI）的操作按钮为（）。

A.

B.

C.

D.

绝缘子串所受水平荷重的大小是由水平档距决定的