You can only be sure of _____ you have at present;you cannot be sure of something _____ you might get in the future.
______the address, Tom sent the email to his teacher.
They all wanted to stop working because they were tired, but______of them would say sl.
.______Hard you may try, you can’t possibly persuade Tom to give up smoking, for he is so addicted to it.
Every year, Tom remembers to have some flowers______to her mother on her birthday.
It’s not easy to learn English well. ______as much as possible is necessary.