ADJ. considerable, great | technical | language, oral, reading, written | cycling, skiing, etc.
QUANT. degree, level He taught himself to carve to a high degree of proficiency.
VERB + PROFICIENCY acquire, develop, increase He acquired greater proficiency after a three-month intensive course. | demonstrate, show
PROFICIENCY + NOUN examination, test a language proficiency test | certificate
PREP. ~ in a certificate for proficiency in English