1、【题目】he teacher told them since light ________ (travel) faster than sound,lightning ________ (appear) to go before thunder.

答案：

travels, appears

解析：

暂无解析

1、【题目】Some molecules are large enough ________ (see) under the electronic microscope.

答案：

to be seen

解析：

暂无解析

1、【题目】The floor does not look so bad when ________ (sweep) clean. 

答案：

swept

解析：

暂无解析

1、【题目】Ishallneverforget________(meet)thelatePremierZhouduringhisinspectionofourfactory.

答案：

解析：

1、【题目】Thedirectorrecommendedthatshe________(study)moreEnglishbeforegoingabroad.

答案：

解析：

1、【题目】________(fail)severaltimes,theyneedsomeencouragement.

答案：

解析：

1、【题目】The director recommended that she ________ (study) more English before going abroad.

答案：

study

解析：

暂无解析

1、【题目】________ (fail) several times, they need some encouragement.

答案：

Having failed

解析：

暂无解析

1、【题目】Iwonderifhecouldgetit________(do)beforetomorrow.

答案：

解析：