2. 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.
A、there
B、thick
C、thank
D、thirty
The old man's clothes, ____ old and worn, looked clean and of good quality.
A、if
B、when
C、though
D、since
Tom is a careless person. He forgot ____ the door again when he went out yesterday.