5. Have you decided on a place for the picnic?
你选好野餐的地点了吗?
还能这样说：
Have you made your mind where we go for the picnic?
Have you already selected a place for the picnic?
6. Can you come this Saturday?
星期六怎么样?
还能这样说：
Do you have time this Saturday?
Are you available this Saturday?
应用解析：
Saturday-to-Monday 周末;
Hospital Saturday 为医院募捐的星期六
7. Do not forget to bring matches, or you'll be unable to build a campfire.
别忘了带火柴，否则就点不着火了。
还能这样说：
You must take matches with you, or you will not make a fire.
You have to make a campfire with matches.
谚语：
The fire which lights us at a distance will burn us when near.
远火照明，近火灼人。
8. You need to put on sunglasses for protection against the strong light.
你需要戴上墨镜以防强光的照射。
还能这样说：
Sunglasses are a must, or you may be hurt by the strong light.
Wearing sunglasses is very necessary which can help you avoid the strong light.
应用解析：
be going strong 健康良好，保持旺盛精力，仍然硬朗;
be strong against 坚决反对;
be strong in 擅长;
be strong under 在……坚定不移