This old stamp isn't sticky any more; I shall have to gum it down onto the envelope.
这张旧邮票的背面没黏性了,我得用胶把它粘在信封上。
If you haven't got the special fasteners to fix your photographs into the book, you'll have to gum them on.
如果没有专用的固定物把相片固定在相册中的话,你就得用胶水粘。