to cross one's t's (and dot one's i's) "to be exact" is attested from 1849. Phrase to a T "exactly" is recorded from 1690s, though the exact signification remains uncertain despite much speculation. The measuring tool called a T-square (sometimes suggested as the source of this) is recorded by that name only from 1785. The T-cell (1970) so called because they are derived from the thymus. As a medieval numeral, T represented 160.
实用例句
1. T-shirts are a nice little earner and it's better than the dole.
卖T恤衫来钱容易，比领救济金好。来自柯林斯例句
2. T-shirts now seem almost de rigueur in the West End.
T恤衫现在几乎成了伦敦西区时尚人士的必备之物。来自柯林斯例句
3. He had bare feet, a T-shirt and cords on.
他光着脚，穿着T恤衫和灯芯绒裤子。来自柯林斯例句
4. T-shirts, the epitome of American casualness, have moved upscale.
象征美国休闲风格的T恤，已经向高端消费市场迈进。来自柯林斯例句
5. He wore a T-shirt that had been tie-dyed in bright colours.
