It's hard custom-building an English test for ex-college students whose high school and college English teachers deserve to be shot.
The students already know some of the stuff you're talking about, so they get bored easily with tests that involve the very basics of the language. Trouble is, that's where they may need fine tuning. Too, as a teacher you need to be seven steps ahead of your study group. You've got to be able to anticipate every question they'll likely throw your way.
Now, imagine that you have to brush up on your English simultaneously with a foreign language that:
1. follows a basic sentence pattern that's not normally used in English;
2. makes use of "post"-positions, (instead of prepositions) and particles (instead of articles) ;
3. conjugates past tense verbs as if they were adjectives;
4. treats the conjugation of present- and future tense verbs in practically the same way
I need a tylenol.