今年张大爷的果树收成较差．下列建议不合理的是（　　）

Dear Frank,

    How's it going? How's the weather in Boston? I'm fine. Thank you for your photos and your letter. In your letter, you say you will soon have a long exciting vacation. You are arriving in China for it, aren't you? It's cool and sunny here now, just for visiting. And would you like to come to my house? Let me tell you the way to my house.

    You can take the No.8 bus from the airport (机场). Then you will pass a hotel on your right and go along Renmin Street. Then you go through Heping Street, Center Street and Long Street. When you see a beautiful garden, turn left. Then you go down

    Bridge Street and turn left at New Park. You can see a house with a big tree next to it. That's my house. You can find it easily. Hope you have a good trip.

Yours,

Mingming

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下列关于生物群落的叙述，错误的是（　　）