给外国朋友写英文邮件时哪句话作为开头问候语？

Answer 1

How is everything?一切都好吗？
I hope everything is all right.我希望(你)一切都好。
How are you?你好吗？
How are you getting along these days? I miss you very much.你近来过得如何？我十分想念你。