________spending our vacation in a noisy crowded city,why not try hiking in the country

Do you know where my address book is?　　　　- It________ be in the hall cupboard. I think I saw it this morning.

I wanted nothing but _____,_____ I stayed up all the night

The Bunsen Burner is so named because it is thought ___________ by Robert Bunsen

Most of English learners want to know how the differences between British and American English ____.