234. After the 1911 Revolution, China began to use the Gregorian calendar (solar calendar) and at the same we have also used the lunar calendar(阴历) in which a leap year (闰年)______ every four years.
The salmon dish was _______, wasn’t it?
The conference had been held to discuss the effects of tourism ___ the wildlife in the rainforest.
Specialists may be useful to _____ a situation and suggest solutions.
Problems _____ because they were lack of communication.
While he was ______ about in the street, Mary came up to him.