Sorry. It has been a long time since I last posted an English grammar blog, so here goes...
Yesterday in class, one of my students said "Let's going drinking!!"
This is another common mistake among Japanese students. She should have said...
"Let's GO drinking"
After "Let's..." we always use a simple present verb eg.
"Let's watch a movie"
"Let's eat lunch"
"Let's go home now"
...or the most useful one for talking to beautiful men or ladies in the street...
"Let's go for dinner some time!!"
Try it out on the next beautiful man / woman you find