Please read the following table in HTML format from a webpage and then answer the question in detail according to the table. Each table cell is defined by a <td> and a </td> tag. Each table row starts with a <tr> and ends with a </tr> tag. 'rowspan=m' and 'colspan=n' represents a cell spaning over 'm' rows and 'n' columns.

Webpage title:
Liu Tong (actor)
Table title:
Web series
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=1 > Year </th><th colspan=1 rowspan=1 > Title </th><th colspan=1 rowspan=1 > Role </th><th colspan=1 rowspan=1 > Notes </th></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=3 > 2017 </td><td colspan=1 rowspan=1 > Painting Heart Expert </td><td colspan=1 rowspan=1 > Tie Pi A San </td><td colspan=1 rowspan=1 > Minor role </td></tr>
<tr> <td colspan=1 rowspan=1 > Soul Stitcher </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > Men with Sword 2 </td><td class="highlighted"  colspan=1 rowspan=1 > Zi Yu </td><td colspan=1 rowspan=1 > Minor role </td></tr>
<tr> <td colspan=1 rowspan=2 > 2018 </td><td colspan=1 rowspan=1 > Pretty Man </td><td colspan=1 rowspan=1 > Classmate </td><td colspan=1 rowspan=1 > Guest </td></tr>
<tr> <td colspan=1 rowspan=1 > Hi, I'm Saori </td><td colspan=1 rowspan=1 > Huang Zheng </td><td colspan=1 rowspan=1 > Guest </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > 2019 </td><td class="highlighted"  colspan=1 rowspan=1 > Young Blood Agency </td><td colspan=1 rowspan=1 > Tong Qiu Bai </td><td colspan=1 rowspan=1 > Main </td></tr>
</table>
Question:
What were the main roles played by Tong in 2017 and 2019?
Answer:
Liu Tong played as Zi Yu in the 2017 web series, Men with Sword 2 and acted in the 2019 web series Young Blood Agency.