I can’t remember where I have put that book.Maybe they are ___ which one is not correct.

What is Grace doing——She _____ in the pool.

Did Jack take the doctor’s advice that he ________ in bed for a couple of days?—If only he ________.[ ]

Thefact has worried many scientists ______ the earth is becoming warmer and warmerthese years.

.You should remember the cause and avoid it the next time you __________ the same situation.