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.
We generally have four people working in the shop, but at ____ periods we employ extra hands.
A、top
B、rush
C、tip
D、peak
4.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.