My answers:
$1.$ It is a small house.
$2.$ How wide is the river?
$3.$ There are twelve months in a year.
$4.$ You'd better not to eat too much meat.
$5.$ Because Lan's sick, she didn't go to school yesterday.
$6.$ The stomachache prevented Mr. Thanh from enjoying the meal
$7.$ What is the height of the Big Ben Clock Tower?
$8.$ You don't need to finish the work today.
$9.$ I like beef and so does my sister.
$10.$ She has no friend in Ha Noi
$11.$ When is your birthday?
@Sunn