$1.$ It's very important to keep the environment clean.
- Gerund + S + tobe + adj = It + tobe + adj + to V.
$2.$ The time machine will be shown to the public when it is finished.
- Câu bị động thì tương lai đơn: S + will + be + V (PII) + (by O).
$3.$ He was delighted that he received his aunt's letter.
$4.$ People recycle old car tires to make shoes and sandals.
$5.$ I'm very sad not to be accepted in that group.
$6.$ I haven't spoken to her for three years.
$7.$ Tam used to type faster than she does now.
- "used to" chỉ hành động đã xảy ra và kết thúc ở trong quá khứ.
$8.$ My father asked me to turn down the radio for him.
$9.$ It is Lan's fifteenth birthday next week.
$10.$ When did you starting using the pen?
$@vanw$
