Zheng He started to sail in 1045 to “Western Seas”. In the following 28 years, he made _______ successful travels.
The elderly need special care in winter, as they are _____ to the sudden changes of weather.
As students, we should devote ourselves _____ our study.
Seeing a _____ smile on his face, no one doubtsthat he will get through the driving test.
The first time he had a dinner with some high officials, he felt ____ uneasy.
Don't put your bicycle______ the window. The glass can be easily broken.