Naturalisation online form questions

[vvzcsy]

I am filling my online application and have a few question need to ask.
1) Have you had any other work over the past 10 years or since you came to UK? I have worked before I came to UK, however since I came to UK 5 years ago I did not work at all. So shall I put yes or no for this question?

2) British citizen referee with expired passport. I understand from this forum that it's not a problem that referee has an expired passport, my question is shall I still fill his expired passport number?

3)Partner's citizenship certification reference number. I read many thread said it is the certification number not the reference number which starting with the first letter of the surname. So just double confirming here, it is the 6 digital number at the top right corner of the certificate?

4) Country visited. When I left UK, I sometimes went to a few counties, shall I list them all? As the online form only allow to select one country a time. for example, I left UK on 01/Jan and returned on 10/Jan, that is 01/Jan UK to Singapore, 04/Jan Singapore to Australia, 07/Jan Australia to Singapore and 10/Jan Singapore to UK. I am not sure how to include those details in, if I select each country per line, it also asks me the departure date and return date to UK, but some of the trips are just happened outside UK. any advice please!

5) Have you made any previous UK immigration applications in the UK or abroad? I have applied many time UK visa as a tourist abroad, like 10 times, do I need to list them all? However I cannot remember the details as to the date submitted the application and etc.

Sorry to have so many questions to ask. I am really confused the above. Look forward to have your shared thoughts. Thank you.