Question

 

Give the correct tense or form of the verbs in brackets. 

The world is getting warmer and the oceans are rising. Why _________ this (1. happen) ________________________?  One answer is that it could simply be part of a natural process. After all, there (2. be) __________________ ice ages and long periods of warmth, so we could just (3. experience) ________________________ another warming trend. This kind of answer (4. have) _______________ more supporters a few years ago. What scientists now (5. believe) ______________ is that human activity is the cause. For more than two hundred years, human  (6. gradually/change) __________________________ the atmosphere, mainly as a result of industrial pollution. We (7. create) ______________ an atmosphere around the earth that, like a giant glass container, (8. let) _____________ heat from the sun through and then (9. hold) _____________ it in. _______________ temperatures and sea levels (10. keep)____________ rising? The general answer is unfortunately yes. 

 

Answer 1

1. Happens
2. Are
3. Experience
4. Had
5. Believe
6. Gradually changes
7. Create
8. Let
9. Hold
10. Does- keep