75. Taiji boxing is good _____ health, so the old man began to practise it ten years ago and now he is good _____ it.
Have you ever ___ to the museum ___ we paid a visit last year?
Some intelligent and successful people find _____ difficult to succeed in language learning.
---Do you know when she _________?---Sorry, I don’t. But I’ll let you know when she _________.
The buildings in this modern city are growing tall, some even reaching over 400 meters _______ height.
—Can you come to help us with our work by 5 o’clock?—I don’t know if I can help;________.