sorry guys... here are the much awaited answers... ALL these are basically Qs from OGR which i attempted wrongly...
1. Choice
A is best. The other choices are unidiomatic or unnecessarily wordy, and the pronoun they, which appears in B, C, and E, has no grammatical referent.
2. The clauses beginning What was in A and The thing that was in B cause inconsistencies in verb tense: the use of the new technology cannot logically be described by both the present perfect has been and the past was. In B and D, developing the compact disc is not parallel to the use of new technology to revitalize ... performances; in C, the best answer, the noun development is parallel to use. The phrases none the less ... than in D and no less... as in E are unidiomatic; the correct form of expression, no less ... than, appears in
C, the best choice.
3. All of the choices but
D contain ambiguities. In A and B the words which and where appear to refer to sediments, and in E it is not clear what consistent describes. In A, C, and E, there is no logical place to which there or its could refer. In D, the best choice, the phrase sediments from the Baltic Sea tells where the sediments originate, findings provides a noun for consistent to modify, and in the area clearly identifies where the industrial activity is growing.
4. Choice
C is best because the participle protecting begins a phrase that explains what the shields did. Choices A and B awkwardly use the singular word method to refer to items of military equipment rather than to the use of such items. Also, a method of protecting would be more idiomatic than a method to protect in A or a method protecting in B. In B and D, as is incorrect; also, a protection in D has no noun for which it can logically substitute. Choice E is incomplete; used to protect would have been acceptable.
Please share the difficult Qs you encounter & we all can discuss (this way we all will benefit)... a lot of preaching

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ashish