How do I get into these Shenzhen tourist attractions?

Are these attractions in Shenzhen free to visit?

Which Attractions in Shenzhen are best to visit during each of the four seasons?
Impressions
Shenzhen in Hues
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SIHOO creates healthier environment
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FAQs
What's New
Man becomes city's 900th unrelated stem cell donor
Exhibition documents SZSEZ's 45-year achievements
SZ Reporters Tell Good Stories