There were resources such as coal, iron, gold, and copper deep in the soil, but they remained________.
A: discovered
B: to discover
C: being undiscovered
D: undiscovered
A: discovered
B: to discover
C: being undiscovered
D: undiscovered
D
举一反三
- The U.S. is the world’s largest producer of oil and _______. （ ）。 A: Iron B: Gold C: Coal D: Natural gas
- 5. There are coal, oil, and metal ______ burried deep in the ground. A: sources B: substances C: resources D: properties
- Europe's earlier industrial growth was _____ by the availability of key resources,abundant and cheap labor,coal,iron ore,etc.
- There _____ nothing to say, the girl remained silent. A: was B: has C: were D: being
- An iron and steel works, with several satellite factories, ______ in that city now. A: is built B: is being built C: were built D: are being built
内容
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Genetically engineered crops are sometimes released into the environment before they have been _________. A: slip by undiscovered B: health effects C: adequately tested D: public relations exercise
- 1
Gold __________(discover)in California.
- 2
Madam Curie is believed ___ the radium. A: having discovered B: to discover C: to have discovered D: discovering
- 3
Madame Curie is believed _________ radium (镭). A: discovering B: having discovered C: to have discovered D: to discover
- 4
Grey spot of oat are due to A: Copper B: Iron C: Manganese D: Zinc