What is crucial in the development of ‘babies’ brains?
A、Babies’ ability to focus.
B、Babies’ mastery of skills.
C、Babies’ muscle strength
D、Babies’ near-constant movement.
If John had entered the office ten minutes ago, he____ what we were talking about just now.
A、should know
B、had known
C、would know
D、would have known
3.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.