depressing, mournful, utterly tragic, sorrowful, tragic, pitiful ☊ like: thê thảm → →
katastrophal ☊ 
thảm họa, thê thảm ☊ 
灾难性的 ☊ zāi nàn xìng de katastrophal ☊ thảm họa, thê thảm ☊ ☊ Please let us know if you cannot attend the meeting. ☊ can ☊
For certain personal reasons I shall not be able to attend. ☊ certain ☊
The whole family can join in the fun at Water World. ☊ fun ☊
She could at least have the good manners to let me know she won't be able to attend. ☊ manner ☊
She couldn't attend the meeting so her assistant took her place. ☊ take sb's/sth's place, take the place of sb/sth ☊
She was unable to attend because of the pressure of work. ☊ pressure ☊
I was unable to attend because of a previous engagement. ☊ previous ☊
She will be unable to attend because of a prior engagement. ☊ prior ☊
You may refer to your notes if you want. ☊ refer to sb/sth ☊
Unfortunately, I won't be able to attend the meeting. ☊ unfortunately ☊