5. We will have a seven days' vacation.
我们会有7天的假期。
还能这样说：
A seven days' vacation is given to us soon.
We're going to have a vacation for seven days.
谚语：
Don't praise the day until evening.
尚未成功之事，不可誉之过早。
6. I'm trying to figure out where to go to travel now.
我正考虑去哪儿旅行呢。
还能这样说：
I am thinking about the right place to travel.
Which place is right to go to travel is under my consideration.
应用解析：
make a brilliant figure 崭露头角；放异彩，引人注目，超群出众；
cut a poor figure 出丑；露出可怜相；显得很不像样
7. Could you take care of my plants while I'm on vacation?
我去度假的时候，你可以照顾我的花草吗？
还能这样说：
Would you like to look after my plants when I am on vacation?
Would you like to watch over my plants during my vacation?
应用解析：
a good long while 长久；
a little while 不久，一会儿；
a while ago 刚才；
all the while 始终，一直；
between whiles 间或；
make it worth sb.'s while 酬谢某人，贿赂某人
8. You can join in the group tour we organize.
你可以加入我们组织的旅行团。
还能这样说：
You can take part in our group tour.
You can go to tour together with our group.
应用解析：
join hand in hand 同心协力；
join oneself to 加入；归入；
join up with 汇合；
join...together 把……连成一体；
join up 参军；把……连接起来