However, there are still _________ to overcome. For example, producing EV batteries can be expensive and sometimes causes environmental problems.

Question

BlackTom AI · Accepted Answer

The correct answer is b. challenges because the sentence needs a noun that means problems or obstacles that remain and that can be "overcome."

1) Relevant knowledge points and concepts
- Collocation: the verb phrase "to overcome" commonly pairs with words like "problems," "difficulties," or "challenges."
- Meaning of choices: 
  - repetitions = things done again
  - challenges = difficulties or obstacles
  - transformations = changes or conversions
  - reductions = decreases
- Context clue: the clause that follows ("producing EV batteries can be expensive and sometimes causes environmental problems") describes difficulties, so the blank should name obstacles.

2) Step-by-step reasoning
Step 1: Read the whole sentence: "However, there are still _________ to overcome. For example, producing EV batteries can be expensive and sometimes causes environmental problems." The phrase "to overcome" signals the blank refers to obstacles/difficulties.  
Step 2: Substitute each option into the sentence and evaluate sense and grammar:
- a. "repetitions to overcome" → illogical: repetitions are repeated actions, not obstacles to be overcome in this context.
- b. "challenges to overcome" → natural and idiomatic: challenges = difficulties, fits context about costs and environmental problems.
- c. "transformations to overcome" → odd: transformations are changes, not typically described as things one "overcomes."
- d. "reductions to overcome" → incorrect sense: reductions are decreases; you wouldn’t usually "overcome" a reduction.

3) Intermediate checks
- Grammar: plural noun is appropriate after "there are still"; "challenges" is a countable plural that fits both grammar and meaning.
- Semantic fit: the example clause explicitly lists expensive production and environmental harm — clear examples of challenges.

4) Why the correct answer is correct
"Challenges" directly names difficulties that must be overcome and is the idiomatic collocation with "to overcome." It matches both the syntax and the semantic context.

5) Why other options are incorrect (brief)
- a. repetitions — wrong meaning (not obstacles).
- c. transformations — wrong meaning (changes, not problems).
- d. reductions — wrong meaning (decreases, not issues to overcome).

Conclusion: The best choice is b. challenges, which matches the provided answer.

However, there are still _________ to overcome. For example, producing EV batteries can be expensive and sometimes causes environmental problems.单项选择题

类似问题

What was the world's first widely adopted biodiversity policy?

The aim of the Paris Agreement is to ensure that the earth’s preindustrial temperature is not exceeded by more than º Celsius.

The IPCC's mission is to Blank ______.

Why have most international agreements for environmental protection been based on the honor system?

As was exhibited with the Montreal Protocol and the encouragement of reduced CFC production, trade can be an effective tool to compel compliance with international treaties.

The Stockholm Declaration and UNEP were the result of the Blank ______ first conference on the Human Environment in 1972.

In addition to the direct mission of the Convention on International Trade in Endangered Species (CITES), why was CITES so important?

President Trump hiring a corporate leader from the oil and gas industry to head the Department of Energy is an example of regulatory ; one intention behind this was to change environmental policy.

更多留学生实用工具

智能学习助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单