[单选题]树皮中的外树皮全是死组织，内树皮主要是活组织。( )

正确答案 ：A

正确

[单选题]----I have tried very hard to find a solution to the problem, but in vain ----why not consult with Frank? You see, _________.

正确答案 ：B

two heads are better than one

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