odoo qweb lt gt 为何用不成呢

<t t-foreach="len(company.csbt.replace('，',',').split(','))" t-as="rec">
     <t t-if=" (rec_index !=  0 ) and (rec_index != 1) and (rec_index lt (rec_size - 2))">
        <td >..</td>
     </t>
 </t>>

lt，gt 通不过，百试不得其解，只有换成其它运算

<t t-if=" (rec_index !=  0 ) and (rec_index != 1) and (rec_index != (rec_size - 2)) and (rec_index != (rec_size - 1))">
   <td >..</td>
</t>