根据句意用冠词a、an、the或 / 填空 1.It's ____ my English book. 2.Lucy is from ____USA . 3.It's ____ English book. 4.—What's this? —It's ____ map. 5.It is ____ “L”. 6.—What's this in English? —It's ____ orange. 7.There is —— eraser on the desk. 8.There is ____"u" in "computer.". 9.Monday is ___ first day of a week. 10.Today is my brother's____ sixth birthday.