基站控制器是（）

A:BTS B:MSC C:HIR D:BSC

__溶剂回收洗涤塔C5001塔底产生的异丁烷是（）。

A:HSR B:LSR C:LIR D:HIR

In each of the following groups of words, there are four underlined letters or letter combinations marked A, B, C and D. Compare the underlined parts and identify the one that is different from the others in pronunciation. Mark your answer by blackening the corresponding letter on the answer sheet.（　）

A:hired B:planned C:tried D:defended

A.hired
B.planned
C.tried
D.defended

单项选择题
In each of the following groups of words, there are four underlined letters or letter combinations marked A, B, C and D. Compare the underlined parts and identify the one that is different from the others in pronunciation. Mark your answer by blackening the corresponding letter on the answer sheet.

A:hired B:planned C:tried D:defended