I’ll ask the teacher about past tense. I’m very puzzled about it. — That is just _____ most of our classmates have doubt.

So necessary _____ it to learn about their customs that I will attend a special lecture next week.

In the last few years thousands of films __________ all over the world

. People have always been_______about exactly how life on earth began.

The engine of the ship was out of order and the bad weather________ the helplessness of the crew at sea.