For modern society, the computer is a great________ (发明)。
The young man has no friends here, so he feels I________.
On Mother's Day, my mother was happy because I gave h________ a scarf as a present.
We need to c________ up with a plan to tell people about the city park clean—up.
To my surprise, Sam made a d________ to study Chinese medicine in Beijing.
This is the t________ time I've been to the Heaven Lake after I came here in 2018 and 2019.
